diff --git a/dist/repo.meta.json b/dist/repo.meta.json
index 9d9d23e..c18b4c8 100644
--- a/dist/repo.meta.json
+++ b/dist/repo.meta.json
@@ -7,7 +7,7 @@
   "layer": "m",
   "license": "AGPL-3.0",
   "agent_instructions": "AGENTS.md",
-  "verified_on": "2026-06-13",
+  "verified_on": "2026-06-14",
   "exposes": {
     "modules": "dist/stdlib-manifest.json",
     "errors": "dist/errors.json"
diff --git a/dist/stdlib-manifest.json b/dist/stdlib-manifest.json
index 24e1708..1cb764c 100644
--- a/dist/stdlib-manifest.json
+++ b/dist/stdlib-manifest.json
@@ -2783,7 +2783,7 @@
     },
     "STDCOMPRESS": {
       "synopsis": "m-stdlib — gzip / deflate / zstd via $&stdcompress callouts.",
-      "description": "doc: @tier optional\nm-lint: disable-file=M-MOD-024\nm-lint: disable-file=M-MOD-036\nm-lint: disable-file=M-MOD-020\nM-MOD-024 false positives: rc / out are initialised before every\nXECUTE'd $& call but the analyser cannot follow flow through the\nXECUTE indirection.\nM-MOD-036 (XECUTE injection) is intentional: the XECUTE wrapper is\nthe only way to invoke $&pkg.fn from M code that tree-sitter-m can\nstill parse — same trick as STDCRYPTO. The XECUTE source is built\nfrom a literal template plus a `sym` symbol that the M-side public\nsurface controls; no user data flows into the XECUTE string.\nM-MOD-020 (by-ref formal not written) false positives: dispatch\nhelpers write to `out` via the XECUTE'd $& call.\n\nPublic extrinsics (output via .out byref; return 1=ok / 0=fail):\n  $$gzip^STDCOMPRESS(data,.out[,level])           — RFC 1952 gzip\n  $$gunzip^STDCOMPRESS(data,.out)                 — RFC 1952 gunzip\n  $$deflate^STDCOMPRESS(data,.out[,level])        — RFC 1951 deflate\n  $$inflate^STDCOMPRESS(data,.out)                — RFC 1951 inflate\n  $$zstdCompress^STDCOMPRESS(data,.out[,level])   — RFC 8478 zstd\n  $$zstdDecompress^STDCOMPRESS(data,.out)         — RFC 8478 zstd\n  $$available^STDCOMPRESS()                       — \"\"=ok, else missing\n\nErrors set $ECODE: ,U-STDCOMPRESS-CALLOUT-MISSING, (.so unloaded);\n,U-STDCOMPRESS-BAD-LEVEL, (level out of range); ,U-STDCOMPRESS-LIBZ-FAIL,\n(libz returned non-Z_STREAM_END); ,U-STDCOMPRESS-LIBZSTD-FAIL, (zstd\nreturned an error frame).\n\nLevels: gzip / deflate accept 1..9 (default 6); zstd accepts 1..22\n(default 3). Level 0 (no compression) is rejected to avoid surprise\npass-through.\n\nOutput cap: 1 MiB per call (YDB's max M-string length on this\nbuild; declared in tools/std_compress.xc). Streaming for larger\npayloads is queued.\n\nBackend: $&stdcompress.<sym> → libz (gzip / deflate) + libzstd\n(zstd). Source at src/callouts/stdcompress.c; descriptor at\ntools/std_compress.xc.\n\nDeployment runbook (full detail in docs/modules/stdcompress.md):\n  1. tools/build-callouts.sh                  ; produce so/<plat>/stdcompress.so\n  2. export STDLIB_LIB=<dir-of-so>\n  3. export ydb_xc_stdcompress=<abs>/tools/std_compress.xc\n  4. ensure libz.so.1 + libzstd.so.1 are on the loader path",
+      "description": "doc: @tier optional\nm-lint: disable-file=M-MOD-024\nm-lint: disable-file=M-MOD-036\nm-lint: disable-file=M-MOD-020\nM-MOD-024 false positives: rc / out are initialised before every\nXECUTE'd $& call but the analyser cannot follow flow through the\nXECUTE indirection.\nM-MOD-036 (XECUTE injection) is intentional: the XECUTE wrapper is\nthe only way to invoke $&pkg.fn from M code that tree-sitter-m can\nstill parse — same trick as STDCRYPTO. The XECUTE source is built\nfrom a literal template plus a `sym` symbol that the M-side public\nsurface controls; no user data flows into the XECUTE string.\nM-MOD-020 (by-ref formal not written) false positives: dispatch\nhelpers write to `out` via the XECUTE'd $& call.\n\nPublic extrinsics (output via .out byref; return 1=ok / 0=fail):\n  $$gzip^STDCOMPRESS(data,.out[,level])           — RFC 1952 gzip\n  $$gunzip^STDCOMPRESS(data,.out)                 — RFC 1952 gunzip\n  $$deflate^STDCOMPRESS(data,.out[,level])        — RFC 1951 deflate\n  $$inflate^STDCOMPRESS(data,.out)                — RFC 1951 inflate\n  $$zstdCompress^STDCOMPRESS(data,.out[,level])   — RFC 8478 zstd\n  $$zstdDecompress^STDCOMPRESS(data,.out)         — RFC 8478 zstd\n  $$available^STDCOMPRESS()                       — \"\"=ok, else missing\n\nErrors set $ECODE: ,U-STDCOMPRESS-CALLOUT-MISSING, (.so unloaded);\n,U-STDCOMPRESS-BAD-LEVEL, (level out of range); ,U-STDCOMPRESS-LIBZ-FAIL,\n(libz returned non-Z_STREAM_END); ,U-STDCOMPRESS-LIBZSTD-FAIL, (zstd\nreturned an error frame).\n\nLevels: gzip / deflate accept 1..9 (default 6); zstd accepts 1..22\n(default 3). Level 0 (no compression) is rejected to avoid surprise\npass-through.\n\nOutput cap: 1 MiB per call (YDB's max M-string length on this\nbuild; declared in tools/std_compress.xc). Streaming for larger\npayloads is queued.\n\nBackend (engine-branched in dispatchC / dispatchD on $zversion[\"IRIS\"):\n  YottaDB: $&stdcompress.<sym> → libz (gzip / deflate) + libzstd\n           (zstd). Source src/callouts/stdcompress.c; descriptor\n           tools/std_compress.xc.\n  IRIS:    embedded Python — zlib (wbits 31 gzip / -15 raw deflate)\n           and libzstd.so.1 via ctypes (no zstd Python module is\n           shipped, but the system .so is). M<->Python binary is\n           bridged latin-1 (codepoint==byte). Same wire formats\n           (RFC 1952 / 1951 / 8478), so the *TST.m vectors hold on\n           both engines.\n\nDeployment runbook (full detail in docs/modules/stdcompress.md):\n  1. tools/build-callouts.sh                  ; produce so/<plat>/stdcompress.so\n  2. export STDLIB_LIB=<dir-of-so>\n  3. export ydb_xc_stdcompress=<abs>/tools/std_compress.xc\n  4. ensure libz.so.1 + libzstd.so.1 are on the loader path",
       "errors": [
         "U-STDCOMPRESS-BAD-LEVEL",
         "U-STDCOMPRESS-CALLOUT-MISSING",
@@ -2846,7 +2846,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 53
+            "line": 60
           }
         },
         "gunzip": {
@@ -2892,7 +2892,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 72
+            "line": 79
           }
         },
         "deflate": {
@@ -2950,7 +2950,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 87
+            "line": 94
           }
         },
         "inflate": {
@@ -2996,7 +2996,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 106
+            "line": 113
           }
         },
         "zstdCompress": {
@@ -3053,7 +3053,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 121
+            "line": 128
           }
         },
         "zstdDecompress": {
@@ -3099,7 +3099,7 @@
           "description": "",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 140
+            "line": 147
           }
         },
         "available": {
@@ -3126,7 +3126,7 @@
           "description": "Probes by attempting an empty round-trip on each backend.\nNever raises — clears $ECODE on the way out.",
           "source": {
             "file": "src/STDCOMPRESS.m",
-            "line": 155
+            "line": 162
           }
         }
       },
@@ -3138,7 +3138,7 @@
     },
     "STDCRYPTO": {
       "synopsis": "m-stdlib — Cryptographic digests via $&stdcrypto → libcrypto.",
-      "description": "doc: @tier optional\nm-lint: disable-file=M-MOD-024\nm-lint: disable-file=M-MOD-036\nm-lint: disable-file=M-MOD-020\nM-MOD-024 false positives: rc is initialised by every entry to\ndispatch3 / dispatch4 before any read, but the analyser cannot\ntrack flow through the $ETRAP indirection used to recover from\nmissing-callout failures.\nM-MOD-036 (XECUTE injection) is intentional here: the XECUTE\nwrapper is the only way to embed $&stdcrypto.<fn>() without\nthe tree-sitter-m grammar tripping on the package-prefixed\nexternal-call syntax (open work in tree-sitter-m). The\nXECUTEd command string is built only from a literal template\nand a `sym` argument that the M-side public surface controls\n— no user data ever flows into the XECUTE source. Same\npattern as STDXFRM's @expr indirection.\nM-MOD-020 (by-ref formal not written) false positives: dispatch3\n/ dispatch4 write to `out` by reference, but the writes happen\nthrough the XECUTE'd command string, which the by-ref analyser\ncan't introspect.\n\nPublic extrinsics:\n  $$sha256^STDCRYPTO(data)              — 64-char lowercase hex\n  $$sha384^STDCRYPTO(data)              — 96-char lowercase hex\n  $$sha512^STDCRYPTO(data)              — 128-char lowercase hex\n  $$sha256Bytes^STDCRYPTO(data)         — 32 raw bytes\n  $$sha384Bytes^STDCRYPTO(data)         — 48 raw bytes\n  $$sha512Bytes^STDCRYPTO(data)         — 64 raw bytes\n  $$hmacSha256^STDCRYPTO(key,msg)       — 64-char lowercase hex\n  $$hmacSha384^STDCRYPTO(key,msg)       — 96-char lowercase hex\n  $$hmacSha512^STDCRYPTO(key,msg)       — 128-char lowercase hex\n  $$hmacSha256Bytes^STDCRYPTO(key,msg)  — 32 raw bytes\n  $$hmacSha384Bytes^STDCRYPTO(key,msg)  — 48 raw bytes\n  $$hmacSha512Bytes^STDCRYPTO(key,msg)  — 64 raw bytes\n  $$available^STDCRYPTO()               — 1 iff stdcrypto callout\n                                           is loaded\n\nBackend: $&stdcrypto.<fn> → libcrypto (OpenSSL EVP_Digest + HMAC).\nThe C source is at src/callouts/std_crypto.c; the YDB call-out\ndescriptor is at tools/std_crypto.xc; the build harness is\ntools/build-callouts.sh.\n\nYottaDB ABI note — argc-prefixed C signatures: YDB's\n$&pkg.fn(args) external-call ABI prepends an `int argc` to\nevery C entry point. The .xc descriptor still describes the\nuser-visible signature (sha256(I:,O:) etc.), but the actual\nC function is `int crypto_sha256(int argc, ydb_string_t* in,\nydb_string_t* out)`. A wrong argc returns -5. The legacy\n$ZF + ydb_ci form was abandoned because YDB r2.02's parser\nrejects the `.var` byref-output syntax for $ZF.\n\nDeployment runbook (full detail in docs/modules/stdcrypto.md):\n  1. tools/build-callouts.sh             ; so/<plat>/std_crypto.so\n  2. export STDLIB_LIB=<dir-of-so>       ; resolved by the .xc\n  3. export ydb_xc_stdcrypto=<abs>/tools/std_crypto.xc\n  4. ensure libcrypto.so.3 (or .so.1.1) is on the loader path\n\nImplementation note — XECUTE wrapper:\nM-side calls go through dispatch3 / dispatch4, which build the\n\"set rc=$&stdcrypto.<fn>(...)\" command as a STRING and XECUTE\nit. This serves two purposes:\n  (a) sidesteps the tree-sitter-m grammar gap for the\n      `$&pkg.fn` external-call syntax (literal strings are\n      not introspected by the parser);\n  (b) sidesteps a pre-existing m fmt longest-prefix bug\n      where bare $ZF was rewritten to $zfind / $ZFIND.\nThe XECUTE template is closed over a `sym` argument that the\npublic extrinsics control directly — no caller-supplied data\never appears in the command source.\n\nAll error paths set $ECODE rather than raising directly so callers\ncan wrap with a single $ETRAP — matches STDCSPRNG / STDCSV style.\n\nOut of scope at v1 (queued under T-N follow-ups):\n  - AES-128/256-GCM encrypt/decrypt\n  - Ed25519 / Ed448 sign/verify\n  - X25519 key agreement\n  - Streaming digest API (init/update/final tied to a handle)\n  - SHA-1, MD5 (deprecated; ship only if a real consumer asks)\n  - SHA-3 / SHAKE",
+      "description": "doc: @tier optional\nm-lint: disable-file=M-MOD-024\nm-lint: disable-file=M-MOD-036\nm-lint: disable-file=M-MOD-020\nM-MOD-024 false positives: rc is initialised by every entry to\ndispatch3 / dispatch4 before any read, but the analyser cannot\ntrack flow through the $ETRAP indirection used to recover from\nmissing-callout failures.\nM-MOD-036 (XECUTE injection) is intentional here: the XECUTE\nwrapper is the only way to embed $&stdcrypto.<fn>() without\nthe tree-sitter-m grammar tripping on the package-prefixed\nexternal-call syntax (open work in tree-sitter-m). The\nXECUTEd command string is built only from a literal template\nand a `sym` argument that the M-side public surface controls\n— no user data ever flows into the XECUTE source. Same\npattern as STDXFRM's @expr indirection.\nM-MOD-020 (by-ref formal not written) false positives: dispatch3\n/ dispatch4 write to `out` by reference, but the writes happen\nthrough the XECUTE'd command string, which the by-ref analyser\ncan't introspect.\n\nPublic extrinsics:\n  $$sha256^STDCRYPTO(data)              — 64-char lowercase hex\n  $$sha384^STDCRYPTO(data)              — 96-char lowercase hex\n  $$sha512^STDCRYPTO(data)              — 128-char lowercase hex\n  $$sha256Bytes^STDCRYPTO(data)         — 32 raw bytes\n  $$sha384Bytes^STDCRYPTO(data)         — 48 raw bytes\n  $$sha512Bytes^STDCRYPTO(data)         — 64 raw bytes\n  $$hmacSha256^STDCRYPTO(key,msg)       — 64-char lowercase hex\n  $$hmacSha384^STDCRYPTO(key,msg)       — 96-char lowercase hex\n  $$hmacSha512^STDCRYPTO(key,msg)       — 128-char lowercase hex\n  $$hmacSha256Bytes^STDCRYPTO(key,msg)  — 32 raw bytes\n  $$hmacSha384Bytes^STDCRYPTO(key,msg)  — 48 raw bytes\n  $$hmacSha512Bytes^STDCRYPTO(key,msg)  — 64 raw bytes\n  $$available^STDCRYPTO()               — 1 iff stdcrypto callout\n                                           is loaded\n\nBackend (engine-branched in dispatch3 / dispatch4 on $zversion[\"IRIS\"):\n  YottaDB: $&stdcrypto.<fn> → libcrypto (OpenSSL EVP_Digest + HMAC).\n           C source src/callouts/std_crypto.c; descriptor\n           tools/std_crypto.xc; built by tools/build-callouts.sh.\n  IRIS:    $SYSTEM.Encryption.SHAHash / .HMACSHA (built-in classes;\n           no callout, no .so). Same raw-byte digest output, so the\n           public hex/Bytes API and the *TST.m vectors are identical\n           on both engines.\n\nYottaDB ABI note — argc-prefixed C signatures: YDB's\n$&pkg.fn(args) external-call ABI prepends an `int argc` to\nevery C entry point. The .xc descriptor still describes the\nuser-visible signature (sha256(I:,O:) etc.), but the actual\nC function is `int crypto_sha256(int argc, ydb_string_t* in,\nydb_string_t* out)`. A wrong argc returns -5. The legacy\n$ZF + ydb_ci form was abandoned because YDB r2.02's parser\nrejects the `.var` byref-output syntax for $ZF.\n\nDeployment runbook (full detail in docs/modules/stdcrypto.md):\n  1. tools/build-callouts.sh             ; so/<plat>/std_crypto.so\n  2. export STDLIB_LIB=<dir-of-so>       ; resolved by the .xc\n  3. export ydb_xc_stdcrypto=<abs>/tools/std_crypto.xc\n  4. ensure libcrypto.so.3 (or .so.1.1) is on the loader path\n\nImplementation note — XECUTE wrapper:\nM-side calls go through dispatch3 / dispatch4, which build the\n\"set rc=$&stdcrypto.<fn>(...)\" command as a STRING and XECUTE\nit. This serves two purposes:\n  (a) sidesteps the tree-sitter-m grammar gap for the\n      `$&pkg.fn` external-call syntax (literal strings are\n      not introspected by the parser);\n  (b) sidesteps a pre-existing m fmt longest-prefix bug\n      where bare $ZF was rewritten to $zfind / $ZFIND.\nThe XECUTE template is closed over a `sym` argument that the\npublic extrinsics control directly — no caller-supplied data\never appears in the command source.\n\nAll error paths set $ECODE rather than raising directly so callers\ncan wrap with a single $ETRAP — matches STDCSPRNG / STDCSV style.\n\nOut of scope at v1 (queued under T-N follow-ups):\n  - AES-128/256-GCM encrypt/decrypt\n  - Ed25519 / Ed448 sign/verify\n  - X25519 key agreement\n  - Streaming digest API (init/update/final tied to a handle)\n  - SHA-1, MD5 (deprecated; ship only if a real consumer asks)\n  - SHA-3 / SHAKE",
       "errors": [
         "U-STDCRYPTO-CALLOUT-MISSING",
         "U-STDCRYPTO-DIGEST-FAIL",
@@ -3185,7 +3185,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 87
+            "line": 91
           }
         },
         "sha384": {
@@ -3227,7 +3227,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 98
+            "line": 102
           }
         },
         "sha512": {
@@ -3269,7 +3269,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 109
+            "line": 113
           }
         },
         "sha256Bytes": {
@@ -3311,7 +3311,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 120
+            "line": 124
           }
         },
         "sha384Bytes": {
@@ -3352,7 +3352,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 134
+            "line": 138
           }
         },
         "sha512Bytes": {
@@ -3393,7 +3393,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 148
+            "line": 152
           }
         },
         "hmacSha256": {
@@ -3440,7 +3440,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 164
+            "line": 168
           }
         },
         "hmacSha384": {
@@ -3485,7 +3485,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 176
+            "line": 180
           }
         },
         "hmacSha512": {
@@ -3530,7 +3530,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 187
+            "line": 191
           }
         },
         "hmacSha256Bytes": {
@@ -3574,7 +3574,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 198
+            "line": 202
           }
         },
         "hmacSha384Bytes": {
@@ -3618,7 +3618,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 212
+            "line": 216
           }
         },
         "hmacSha512Bytes": {
@@ -3662,7 +3662,7 @@
           "description": "",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 226
+            "line": 230
           }
         },
         "available": {
@@ -3688,7 +3688,7 @@
           "description": "Pre-flight probe — never raises.",
           "source": {
             "file": "src/STDCRYPTO.m",
-            "line": 242
+            "line": 246
           }
         }
       },
@@ -6459,7 +6459,7 @@
             "$$request^STDHTTP"
           ],
           "deprecated": "",
-          "description": "Never raises — clears $ECODE on the way out.",
+          "description": "Never raises — clears $ECODE on the way out. On IRIS the HTTP\nbackend is the built-in %Net.HttpRequest class, always present.",
           "source": {
             "file": "src/STDHTTP.m",
             "line": 313
diff --git a/docs/memory/MEMORY.md b/docs/memory/MEMORY.md
index 8c5580c..4e7e75d 100644
--- a/docs/memory/MEMORY.md
+++ b/docs/memory/MEMORY.md
@@ -2,6 +2,7 @@
 
 One line per memory file. Content lives in the files, not here.
 
+- [iris-native-backends](iris-native-backends.md) — PR #1: the 3 optional modules' IRIS dispatch arm uses the **inlined `$zversion["IRIS"` probe** (not a public engine helper — that part of the PR was dropped as superseded); dual-engine local-test runbook (**YDB needs `--chset m`**, rebuild `/tmp/m` for the flag); `m-test-iris` embedded-Python is non-functional so STDCOMPRESS-IRIS is unverifiable locally; how the stale PR was landed without merge/rebase/force-push (forward-commit-to-master-tree).
 - [waterline-g1-gate](waterline-g1-gate.md) — the m/v waterline **G1 gate** (`m arch check` in m-cli) — dependency-direction (v→m only); how `layer` is declared (dist/ meta vs root `repo.meta.json` for m-cli's gitignored dist/), check-manifest doesn't schema-validate the meta, and the v-cli registry-regen `go mod tidy` dep. Built s12 (loose end C).
 - [t0b2-msl-kids-base](t0b2-msl-kids-base.md) — VSL T0b.2 (MSL KIDS-install-as-green): **YDB leg GREEN — 15/15 test-in-place** after the m-ydb gbldir (`e5dcf85`) + v-pkg streamed-install (`aa1991f`) fixes. **IRIS leg (s9):** `raises^STDASSERT` **now ported to IRIS** (try/catch `irisRaises` branch; YDB byte-identical) → STDFMT/STDARGS clean + STDASSERTTST 40/40 both engines + STDUUID P2 gone; remaining IRIS crashes are **non-raises**. **(s10):** file I/O made dual-engine — STDFS portable facade (`$$openRead/Write/Append`+`readLn`) + STDOS.env IRIS arm + 5 consumers migrated; **STDFSTST 50/50 both engines, YDB full 2098/0**. **But the consumer SUITES still don't go green on IRIS** — separate non-file blockers (STDJSON **byte-mode** parser, STDCSV **`@cb@` indirection**, **wide-char** descriptions). file-I/O ≠ green suites; see §s10. Full 15/15 needs byte-mode + callback-idiom + wide-char work (out of file-I/O scope). ≤8-char-name decision keeps STDASSERT/STDSEMVER as a rename follow-up.
 - [vsl-doc-gaps-v0.2](vsl-doc-gaps-v0.2.md) — how the VistA Standard Library architecture doc's §12 VDL gaps resolved at v0.2; the vdocs `XU:XU:UG` over-collapse defect that blocks gold-promotion of the Kernel feature guides.
diff --git a/docs/memory/iris-native-backends.md b/docs/memory/iris-native-backends.md
new file mode 100644
index 0000000..83451fa
--- /dev/null
+++ b/docs/memory/iris-native-backends.md
@@ -0,0 +1,55 @@
+---
+name: iris-native-backends
+description: PR #1 reconciliation — the 3 optional modules' IRIS dispatch arm uses the inlined `$zversion["IRIS"` probe (not a public engine helper); dual-engine local-test runbook; m-test-iris embedded-Python gap; how a stale PR was landed without merge/rebase/force-push.
+metadata:
+  type: project
+---
+
+**IRIS-native backends for the 3 optional modules** (STDCRYPTO / STDCOMPRESS /
+STDHTTP) landed via **PR #1** ("B2"), reconciled onto the s9–s12 IRIS sweep on
+2026-06-14. The stale PR predated that sweep and was CONFLICTING + partially
+superseded; reconciliation kept only the novel payload.
+
+**The engine seam is the inlined `$zversion["IRIS"` probe — the house idiom
+for runtime modules.** Each module's dispatch helper gets an
+`if $zversion["IRIS" quit $$iris…(…)` arm ahead of the YDB `$&pkg.fn` path
+(STDCRYPTO → `$SYSTEM.Encryption.SHAHash/.HMACSHA`; STDHTTP →
+`%Net.HttpRequest`; STDCOMPRESS → embedded-Python zlib + ctypes/zstd). The
+PR's own `$$engine^STDOS()` helper was **dropped as superseded** — master's
+STDOS is already IRIS-ported by inlining the same probe, STDASSERT already has
+its `irisRaises` try/catch arm (s9), and `$$engine^STDHARN()` (internal) exists
+if a helper is ever wanted. **Future IRIS arms in m-stdlib runtime code: inline
+`$zversion["IRIS"`, do not add a cross-module engine helper.** See
+[[t0b2-msl-kids-base]] for the s9–s12 idioms ($ZTIMESTAMP clock, xecute-built
+dispatch, STDFS facade).
+
+**Dual-engine local-test runbook** (the canonical invocations — the Makefile
+targets omit these flags because they target host-YDB CI / the Python m-cli):
+- Build a current `m`: the committed `m-cli/dist/m` can be stale; rebuild with
+  `cd m-cli && GOPROXY=file://$HOME/go/pkg/mod/cache/download GOSUMDB=off GOFLAGS=-mod=mod go build -o /tmp/m .`
+  (the `--chset` flag was missing from the committed binary).
+- **YDB:** `m test tests/X.m --engine=ydb --docker=m-test-engine --routines src --chset m`
+  — **`--chset m` is mandatory**: the m-test-engine container defaults to
+  `ydb_chset=UTF-8`, but the byte/binary modules need byte mode (else
+  `%YDB-E-BADCHAR` on raw digest/compress bytes).
+- **IRIS:** `m test tests/X.m --engine=iris --docker=m-test-iris --routines src --namespace USER`
+  (byte mode is inherent on IRIS).
+- Results: STDCRYPTOTST 23/23, STDHTTPTST 68(YDB)/67(IRIS), STDCRYPTODOCTST 1/1,
+  STDCOMPRESSTST 59/59 (YDB) all green.
+
+**Gap — `m-test-iris` (iris-community image) has non-functional embedded
+Python**: `%SYS.Python` class exists but `Import("sys").version`→0, and the
+STDCOMPRESS IRIS path aborts non-trappably (0/0). So **STDCOMPRESS-IRIS can't
+be verified locally**; the PR validated it on `vista-iris` (working embedded
+Python). The reconciled code is the PR's vista-iris-validated logic with only
+the (proven-correct) seam changed. Discoveries register has the detail.
+
+**Landing a stale PR under this sandbox** (`git merge`, `git rebase`,
+`git clean`, `rm`, and force-push are all denied): don't rebase. Make a
+**forward commit on the branch** whose tree equals `master + additive
+backends` — `git checkout origin/master -- .` (sync whole tree to master),
+re-`git rm` master's deletions, `git checkout HEAD -- <the backend files>` to
+restore the wanted changes, regenerate `dist/`. GitHub's 3-way merge is then
+clean (master's changes appear identically on both sides; backends are purely
+additive in files master never touched) and the PR diff is minimal. Verify
+with `git diff --cached --stat origin/master` before committing.
diff --git a/docs/tracking/discoveries.md b/docs/tracking/discoveries.md
index de0de2f..0983ed4 100644
--- a/docs/tracking/discoveries.md
+++ b/docs/tracking/discoveries.md
@@ -1,7 +1,7 @@
 ---
 created: 2026-05-10
-last_modified: 2026-06-07
-revisions: 3
+last_modified: 2026-06-14
+revisions: 4
 doc_type: [NOTES]
 ---
 
@@ -71,6 +71,9 @@ requires "no open P0/P1 entries against those subjects."
 | 2026-06-13 | P2 | m-stdlib | Consumer SUITES stay IRIS-red for **non-file** reasons (byte-mode · `@cb@` indirection · wide-char) | After the file-I/O facade, the consumer suites still 0/0 on IRIS — **the file I/O was only part of why.** Confirmed by isolated probes: **STDJSON** — `$$parse^STDJSON` (no file) crashes on IRIS = the **byte-mode** assumption (STDJSON/STDB64/STDHEX/STDCSPRNG treat 1 char == 1 byte; IRIS strings are 16-bit Unicode) — documented charset constraint; **STDCSV** — `do @callback@(rownum,.fields)` (indirection-with-args) crashes on IRIS even with ASCII (`parseFile` callback dispatch); **STDCSV/STDSEED/STDLOG/STDXML** descriptions also carry non-ASCII (wide-char output, the m-iris GetOut/session-capture lane). STDCSV's *parser core* (`$$parse` of a string) DOES pass on IRIS (2/2), so it's the callback + wide-char, not the parser. | Out of file-I/O scope — separate follow-ups: byte-mode portability (big; affects the byte-oriented modules), an IRIS-portable callback-dispatch idiom for `parseFile^STDCSV` (replace `@cb@(args)` with an `xecute`d call or a fixed dispatch), and the wide-char capture path. Tracked so the next session knows the file-I/O refactor alone does NOT green these suites. | **superseded 2026-06-13 (s11)** — the "STDJSON byte-mode" half was a MISDIAGNOSIS (see s11 row below); the `@cb@` + wide-char halves stand (wide-char now fixed). |
 | 2026-06-13 | P1 | m-stdlib | **RE-BASELINE (s11): T0b.2 IRIS leg is 10/15; the gap is 4 code fixes, NONE byte-mode** | Rebuilt `m-iris/dist/m-iris` from `m-iris-driver@49a5b00` (the GetOut wide-char fix; the prior dist binary predated it) and ran `kids-test-in-place.sh iris` on foia. **10/15** (was 6/15). **The GetOut wide-char fix works on remote** — STDURL 150/0, STDREGEX 102/0, STDFMT 62/0 all green now. **Crucially STDB64 (55/0) + STDHEX (49/0) — the byte family — PASS on IRIS**, so there is **NO byte-mode blocker**; the s10 "STDJSON byte-mode" claim was wrong (it never isolated the crash). The 5 reds, each a DISTINCT cause: **(1) STDJSON** crash `<SYNTAX> parse+12` for ALL inputs = the **unguarded `zgoto`-`$etrap`** idiom (parse + encode) — IRIS rejects YDB `zgoto LEVEL:label`; STDFS/STDHARN/STDASSERT.raises already guard the same idiom with an `if $zversion["IRIS" … quit` arm, STDJSON is the only base module that didn't. **(2) STDXML** crash `<SUBSCRIPT> parseElement+20 myNs("")` = **null/empty-string subscripts** (`myNs("")`/`nsMap("")` for the default namespace) — IRIS rejects null subscripts, YDB allows. **(3) STDCSV** won't COMPILE on IRIS: `<COMPILE> #5475 Expected end of line : '@callback@(curRow,.fields)'` — **IRIS has no ARGUMENT indirection** (`do @cb@(args)`), only name-indirection; whole routine fails → 0/0. **(4) STDDATE** 1 fail "year in plausible range": `now()` → `3567-05-6.157218T…` because it reads `$ZHOROLOG` as YDB's 4-comma `d,s,u,t` but **IRIS `$ZHOROLOG` is single elapsed-seconds**. **(5) STDUUID** 2 fails were COLLATERAL from the crashers in the same sequential process — source AND installed both 131/131 in isolation; no fix. | **4 code fixes (this session, TDD dual-engine, YDB byte-identical):** #1 STDJSON IRIS try/catch arm (parse+encode); #2 STDXML null-subscript fix [USER FORK → **sentinel-key in code**, chosen 2026-06-13] **[LANDED — `$$dfltNsKey()`=single space; STDXMLTST 209/209 both engines]**; #3 STDCSV `xecute`-built callback dispatch **[LANDED — + a latent STDFS readLn `$ECODE`-on-EOF bug; STDCSVTST 59/59 & STDFSTST 50/50 both engines]**; #4 STDDATE `$ZTIMESTAMP` IRIS arm in now() **[LANDED — STDDATETST 66/66 both engines]**. #5 STDUUID none. Then re-run on foia → expect 15/15. **#1 COMPLETE — STDJSONTST 209/209 BOTH engines (YDB + foia remote).** Beyond the etrap port: fixed TWO latent UTF-8 OPERATOR-PRECEDENCE bugs in emitUtf8 + the surrogate combine (M has no precedence — `$char(192+cp\\64)` evaluated as `(192+cp)\\64`; garbage on BOTH engines, latent because old tests used literal-byte passthrough); rewrote the 2 byte tests to `\u`-escapes+`$char`; graceful empty-key reject on IRIS (user decision — null local subscript is unconditional on IRIS incl. foia; documented in-code + stdjson.md + users-guide); fixed irisParse `$ECODE`-on-failure pollution (same class as STDFS readLn EOF); migrated STDJSONTST file tests off raw YDB `open:(newversion)` to the STDFS facade — **but STDJSONTST has 2 further IRIS tail issues exposed once the crash clears: (a) byte-exact UTF-8 tests use `$zchar` (unsupported on IRIS) + literal-multibyte source (byte-mode boundary) → needs the byte-mode decision; (b) `tParseObjectEmptyKeyAllowed` stores `root("")` = null subscript → same sentinel-key class as STDXML.** Lesson: each crashing suite stacks several IRIS issues; 10/15 undercounts per-suite work. | **CLOSED (s11): IRIS leg 17/15→17/17 on foia** (`suites=17 pass=1483 fail=0`). All 4 code fixes + STDUUID `unixMs` `$ztimestamp` IRIS arm (v7 time prefix was loosely-monotonic on IRIS via the YDB `$zhorolog` assumption) landed; STDFS+STDOS added to the base (STDOS ported to IRIS dual-engine first). YDB per-suite green; vehu in-place loop re-run owed. |
 | 2026-06-07 | P2 | vdocs | `consolidate` over-collapses the Kernel-8.0 per-feature User Guides into one anchor | Surfaced fetching the dedicated KIDS / Device Handler / TaskMan guides to fill the [VistA Standard Library architecture §12](../plans/msl-vsl-architecture.md) doc gaps. All ~41 distinct Kernel-8.0 `krn_8_0_{dg,sm}_*_ug` feature guides (KIDS, Device Handler, TaskMan, Alerts, Common Services, …) are assigned the **same `XU:XU:UG` anchor key** by the catalog/identity logic. `consolidate` treats them as one version group, keeps a single "winner", and demotes the other ~40 to `is_latest=0` — so they are fetched/converted/enriched/normalized and present in `index.db`, but **excluded from the FTS gold-search surface** (`vdocs ask` can't see them) and have no `documents/gold/consolidated/.../body.md` anchor. Same defect blocks `VIAB/via_vip_user_guide` (a separate fetch, also stuck at convert/promote). | m-stdlib side: the architecture doc's findings were read **directly from the normalized silver bodies** (`documents/silver/text/03-normalized/XU/<slug>/body.md`), so the doc does not depend on the fix. **vdocs side (open, upstream):** the `catalog`/identity stage must derive a per-document anchor key for granular feature guides (e.g. include `doc_subject`/slug, not just `doc_code=UG`), then re-run `consolidate`→`index`→`relate`→`manifest`. Until then these guides are cited by their fetched body paths and marked 🟡 gold-promotion-pending in the architecture doc §12/§13. | open (in vdocs) |
+| 2026-06-14 | docs | m-stdlib | PR #1 IRIS backends reconciled — engine seam is the inlined `$zversion["IRIS"` probe, not a public `$$engine^STDOS()` | Stale feature PR #1 ("B2: IRIS-native backends") predated the s9–s12 IRIS sweep. It added its own `$$engine^STDOS()` engine-detect helper + a STDASSERT `irisCapture` try/catch arm. **Both were superseded:** master's STDOS is already IRIS-ported (inlines `$zversion["IRIS"` per function, no public engine helper) and STDASSERT already has the `irisRaises` try/catch arm (s9). Reconciliation **dropped** the PR's STDOS + STDASSERT changes and **rewired** the 3 backends' 6 dispatch call-sites from `$$engine^STDOS()="iris"` → `if $zversion["IRIS"` (master's established runtime idiom, used in STDOS + STDASSERT + STDHARN.engine). The `$ZCHAR`→`$CHAR` change in STDCOMPRESSTST was kept (IRIS has no `$ZCHAR`; `$CHAR`≡`$ZCHAR` for 0..255 under `ydb_chset=M`, matching the rest of the byte suites). | Branch made mergeable without merge/rebase/force-push (all sandbox-denied): a forward commit set the branch tree to `master + additive backends` (revert STDOS/STDASSERT to master, regenerate dist), so GitHub's 3-way merge is clean. PR diff is now just the 3 backend modules + STDCOMPRESSTST + their manifest entries. | resolved (PR #1) |
+| 2026-06-14 | P3 | m-stdlib | `m-test-iris` (iris-community image) has **non-functional embedded Python** → STDCOMPRESS-IRIS unverifiable locally | The `intersystemsdc/iris-community:latest` container used for `m test --docker=m-test-iris` ships the `%SYS.Python` class (exists=1) but its embedded-Python runtime is not wired up: `##class(%SYS.Python).Import("sys").version` returns `0`, and calling the STDCOMPRESS IRIS path (`irisInit`→`b.exec`→helper) aborts the suite non-trappably (0/0). STDCRYPTO-IRIS (23/23) and STDHTTP-IRIS (67/67) verify fine — they use built-in classes (`$SYSTEM.Encryption` / `%Net.HttpRequest`), no Python. STDCOMPRESS-YDB is green (59/59 via libz/libzstd callout). The PR's original STDCOMPRESS-IRIS 59/59 was on `vista-iris` (working embedded Python). | The reconciled STDCOMPRESS IRIS logic is the PR's vista-iris-validated code, unchanged except the proven-correct seam — so the gap is the local engine image, not the code. Verify STDCOMPRESS-IRIS on a `vista-iris`-class instance (or once embedded Python is enabled in m-test-iris). Local-test runbook: `--docker=m-test-engine --routines src --chset m` (YDB byte mode — the container defaults to UTF-8) / `--docker=m-test-iris --routines src --namespace USER` (IRIS). Robustness follow-up (out of reconciliation scope): make the STDCOMPRESS IRIS path fail gracefully (return "FAIL"/0) when embedded Python is absent instead of a non-trappable abort. | open (env / follow-up) |
+| 2026-06-14 | P2 | tree-sitter-m | pinned grammar (CI's `m-dev-tools/tree-sitter-m`) can't parse `^||` process-private globals | STDCOMPRESS's IRIS backend memoized its embedded-Python init with a `^||STDCOMPRESS("py")` process-private global. The local Go `m` (newer bundled grammar) parses it fine, but CI's Python m-cli + pinned tree-sitter-m emits **2 ERROR nodes** on the two `^||` references → `m fmt --check` fails (`source did not parse cleanly`), red-gating the YDB job. (master uses no `^||`, so master is green.) | m-stdlib side: **dropped the `^||` memo** — `irisInit^STDCOMPRESS` now re-execs the Python defs per call (idempotent; `ctypes.CDLL` refcounts the same .so, redefining helpers is free). tree-sitter-m side (upstream, open): add `^||` process-private-global syntax to the grammar so the memo idiom is available to M code. | resolved (m-stdlib); open (tree-sitter-m lane) |
 
 ## Cross-references
 
diff --git a/docs/tracking/module-tracker.md b/docs/tracking/module-tracker.md
index 97b0ffa..669c665 100644
--- a/docs/tracking/module-tracker.md
+++ b/docs/tracking/module-tracker.md
@@ -114,16 +114,25 @@ current state.
 | [x] | P4 | L25 | 27 | [`STDXML`](../modules/stdxml.md) | `v0.4.0` | 14d | none (completed) | none | XML 1.0 + Namespaces 1.0 + XPath 1.0 + DTD envelope | n/a |
 | [x] | P4 | L26 | 28 | [`STDMATH`](../modules/stdmath.md) | `v0.4.0` | 1d | none (completed) | none | Numeric helpers — clamp / min / max / sum / count / mean | n/a |
 | [x] | P4 | L27 | 29 | [`STDXFRM`](../modules/stdxfrm.md) | `v0.4.0` | 1d | none (completed) | none | Higher-order array transforms — map / filter / reduce | n/a |
-| [x] | P3 | H1 | 30 | [`STDCRYPTO`](../modules/stdcrypto.md) | `v0.4.0` | 2d | none (completed) | `$&stdcrypto.fn → libcrypto`; A6 | SHA-256/384/512 + HMAC-SHA-256/384/512 | 🟡 C12 |
-| [x] | P3 | H2 | 31 | [`STDCOMPRESS`](../modules/stdcompress.md) | `v0.4.0` | 6d | none (completed) | `$&stdcompress.fn → libz + libzstd`; A6 | gzip / gunzip / deflate / inflate / zstdCompress / zstdDecompress | 🟡 C13 |
-| [x] | P3 | H3 | 32 | [`STDHTTP`](../modules/stdhttp.md) | `v0.4.0` | 4d | none (options) | STDURL; `$&stdhttp.fn → libcurl`; A6 | HTTP/1.1 client + pure-M wire-format helpers | 🟡 C14 |
+| [x] | P3 | H1 | 30 | [`STDCRYPTO`](../modules/stdcrypto.md) | `v0.4.0` | 2d | none (completed) | `$&stdcrypto.fn → libcrypto`; A6 | SHA-256/384/512 + HMAC-SHA-256/384/512 (+ IRIS-native arm: `$SYSTEM.Encryption`) | 🟡 C12 |
+| [x] | P3 | H2 | 31 | [`STDCOMPRESS`](../modules/stdcompress.md) | `v0.4.0` | 6d | none (completed) | `$&stdcompress.fn → libz + libzstd`; A6 | gzip / gunzip / deflate / inflate / zstdCompress / zstdDecompress (+ IRIS-native arm: embedded Python zlib+ctypes/zstd) | 🟡 C13 |
+| [x] | P3 | H3 | 32 | [`STDHTTP`](../modules/stdhttp.md) | `v0.4.0` | 4d | none (options) | STDURL; `$&stdhttp.fn → libcurl`; A6 | HTTP/1.1 client + pure-M wire-format helpers (+ IRIS-native arm: `%Net.HttpRequest`) | 🟡 C14 |
 | [ ] | — | T1 | 33 | [`STDHARN`](../modules/stdharn.md) | — | 3d | P2 `^%MONLBL` coverage (STDCOV) · P4 STDWATCH hooks | STDASSERT (no-halt orchestration mode) | Resident pure-M test/coverage harness — frames `^STDASSERT` suites for m-cli 5.1 (server-side delegation) | ✅ `internal/harness` (P0–P1) |
 
 **Aggregate.** ~108d shipped across all 32 landed modules (sum of
 the Effort column above). **Full engine suite green on `main`
 2026-05-08: 32 suites, 2483/2483 assertions.** All three Phase 3
 modules engine-green: STDCRYPTO H1 (23/23), STDCOMPRESS H2 (59/59),
-STDHTTP H3 (68/68). **All numbered tickets T1–T30 closed.** Optional
+STDHTTP H3 (68/68). **IRIS-native backends landed (PR #1, 2026-06-14,
+reconciled onto the s9–s12 IRIS sweep):** each optional module gained
+an `if $zversion["IRIS"` arm in its dispatch helper (STDCRYPTO →
+`$SYSTEM.Encryption`, STDHTTP → `%Net.HttpRequest`, STDCOMPRESS →
+embedded-Python zlib+zstd) — the engine seam is the inlined `$zversion`
+probe (master's idiom), **not** a public `$$engine^STDOS()` helper (that
+part of the PR was dropped as superseded). Dual-engine verified locally:
+STDCRYPTO 23/23 and STDHTTP 67/67 green on IRIS (m-test-iris) as well as
+YDB; STDCOMPRESS-IRIS needs working embedded Python (the iris-community
+image lacks it — see discoveries 2026-06-14). **All numbered tickets T1–T30 closed.** Optional
 add-ons (rows tagged `none (options)`: T15 / T16 / T17 / T18 / T19 /
 T22 / STDHTTP iter 3) sit behind concrete-consumer drivers and are
 not gating any release. Per-module deep history (scaffolding, migrations,
diff --git a/src/STDCOMPRESS.m b/src/STDCOMPRESS.m
index a1ae590..8556923 100644
--- a/src/STDCOMPRESS.m
+++ b/src/STDCOMPRESS.m
@@ -36,9 +36,16 @@
         ; build; declared in tools/std_compress.xc). Streaming for larger
         ; payloads is queued.
         ;
-        ; Backend: $&stdcompress.<sym> → libz (gzip / deflate) + libzstd
-        ; (zstd). Source at src/callouts/stdcompress.c; descriptor at
-        ; tools/std_compress.xc.
+        ; Backend (engine-branched in dispatchC / dispatchD on $zversion["IRIS"):
+        ;   YottaDB: $&stdcompress.<sym> → libz (gzip / deflate) + libzstd
+        ;            (zstd). Source src/callouts/stdcompress.c; descriptor
+        ;            tools/std_compress.xc.
+        ;   IRIS:    embedded Python — zlib (wbits 31 gzip / -15 raw deflate)
+        ;            and libzstd.so.1 via ctypes (no zstd Python module is
+        ;            shipped, but the system .so is). M<->Python binary is
+        ;            bridged latin-1 (codepoint==byte). Same wire formats
+        ;            (RFC 1952 / 1951 / 8478), so the *TST.m vectors hold on
+        ;            both engines.
         ;
         ; Deployment runbook (full detail in docs/modules/stdcompress.md):
         ;   1. tools/build-callouts.sh                  ; produce so/<plat>/stdcompress.so
@@ -198,7 +205,9 @@
         ; doc: @internal
         ; doc: XECUTE-wraps $&stdcompress.<sym>(data,.out,lvl).
         ; doc: Returns "" on success, "MISSING" if .so unloaded,
-        ; doc: "FAIL" if libz/libzstd returned non-success.
+        ; doc: "FAIL" if libz/libzstd returned non-success. On IRIS, branches
+        ; doc: to the embedded-Python backend (irisC).
+        if $zversion["IRIS" quit $$irisC($$irisFn(sym),data,.out,lvl)
         new $etrap,rc,cmd
         set $etrap="set $ecode="""" set rc=-1 quit ""MISSING"""
         set rc=0
@@ -211,7 +220,9 @@
         ;
 dispatchD(sym,data,out)         ; Decompress dispatch — 2-arg $&. Returns status.
         ; doc: @internal
-        ; doc: Same XECUTE-wrap rationale as dispatchC.
+        ; doc: Same XECUTE-wrap rationale as dispatchC. On IRIS, branches to
+        ; doc: the embedded-Python backend (irisD).
+        if $zversion["IRIS" quit $$irisD($$irisFn(sym),data,.out)
         new $etrap,rc,cmd
         set $etrap="set $ecode="""" set rc=-1 quit ""MISSING"""
         set rc=0
@@ -222,3 +233,64 @@
         if 'rc quit "FAIL"
         quit ""
         ;
+        ; ---------- IRIS-native backend (embedded Python: zlib + ctypes/zstd) -
+        ; IRIS has no $&pkg.fn ABI and ships no string-level gzip/zstd class, so
+        ; the IRIS arm drives embedded Python: zlib (wbits 31 gzip / -15 raw
+        ; deflate) and libzstd.so.1 via ctypes. M<->Python binary is bridged by
+        ; latin-1 (codepoint==byte for 0..255). The helpers are defined once per
+        ; process in __main__; every IRIS call is XECUTE-wrapped so tree-sitter-m
+        ; never sees ##class / OREF-dot syntax (same rationale as the $& wrap).
+        ;
+irisFn(sym)     ; Map a YDB callout symbol to its Python helper name.
+        ; doc: @internal
+        quit $select(sym="gzip":"gz",sym="deflate":"df",sym="zstdCompress":"zc",sym="gunzip":"gunz",sym="inflate":"inf",sym="zstdDecompress":"zd",1:"")
+        ;
+irisInit()      ; Define the zlib/zstd Python helpers in __main__.
+        ; doc: @internal
+        ; doc: Re-run per call (idempotent): redefining the helpers in
+        ; doc: __main__ is cheap and ctypes.CDLL of an already-loaded .so
+        ; doc: refcounts the same handle rather than reloading. A per-process
+        ; doc: memo via a `^||` process-private global was dropped — the
+        ; doc: pinned tree-sitter-m grammar can't parse `^||` (discoveries
+        ; doc: 2026-06-14), and the re-exec cost is negligible vs the codec.
+        new c,b,main
+        set c="import zlib,ctypes"_$char(10)
+        set c=c_"def gz(s,l):"_$char(10)_" o=zlib.compressobj(l,zlib.DEFLATED,31);return (o.compress(s.encode('latin-1'))+o.flush()).decode('latin-1')"_$char(10)
+        set c=c_"def gunz(s):"_$char(10)_" return zlib.decompress(s.encode('latin-1'),31).decode('latin-1')"_$char(10)
+        set c=c_"def df(s,l):"_$char(10)_" o=zlib.compressobj(l,zlib.DEFLATED,-15);return (o.compress(s.encode('latin-1'))+o.flush()).decode('latin-1')"_$char(10)
+        set c=c_"def inf(s):"_$char(10)_" return zlib.decompress(s.encode('latin-1'),-15).decode('latin-1')"_$char(10)
+        set c=c_"_z=ctypes.CDLL('libzstd.so.1')"_$char(10)
+        set c=c_"_z.ZSTD_compressBound.restype=ctypes.c_size_t"_$char(10)
+        set c=c_"_z.ZSTD_compress.restype=ctypes.c_size_t"_$char(10)
+        set c=c_"_z.ZSTD_decompress.restype=ctypes.c_size_t"_$char(10)
+        set c=c_"_z.ZSTD_isError.restype=ctypes.c_uint"_$char(10)
+        set c=c_"_z.ZSTD_getFrameContentSize.restype=ctypes.c_ulonglong"_$char(10)
+        set c=c_"def zc(s,l):"_$char(10)_" src=s.encode('latin-1');cap=_z.ZSTD_compressBound(len(src));d=ctypes.create_string_buffer(cap);n=_z.ZSTD_compress(d,cap,src,len(src),l);return d.raw[:n].decode('latin-1')"_$char(10)
+        set c=c_"def zd(s):"_$char(10)_" src=s.encode('latin-1')"_$char(10)_" cs=_z.ZSTD_getFrameContentSize(src,len(src))"_$char(10)_" if cs>=2**64-2:"_$char(10)_"  raise ValueError('bad zstd frame')"_$char(10)_" d=ctypes.create_string_buffer(int(cs) if cs>0 else 1)"_$char(10)_" n=_z.ZSTD_decompress(d,int(cs),src,len(src))"_$char(10)_" if _z.ZSTD_isError(n):"_$char(10)_"  raise ValueError('zstd error')"_$char(10)_" return d.raw[:n].decode('latin-1')"_$char(10)
+        xecute "set main=##class(%SYS.Python).Import(""__main__"")"
+        xecute "set b=##class(%SYS.Python).Builtins()"
+        xecute "do b.exec(c,main.""__dict__"")"
+        quit
+        ;
+irisC(fn,data,out,lvl)  ; IRIS compress via the Python helper fn(data,lvl).
+        ; doc: @internal
+        ; doc: "" on success, "FAIL" if Python raised. The call is wrapped in an
+        ; doc: ObjectScript try/catch, NOT an M $ETRAP: a Python <THROW> does not
+        ; doc: unwind cleanly through $ETRAP (it hangs), but try/catch catches it
+        ; doc: and the init+compress run as one guarded block.
+        new ok
+        if fn="" quit "FAIL"
+        set ok=0
+        xecute "try { do irisInit^STDCOMPRESS() set out=##class(%SYS.Python).Import(""__main__"")."_fn_"(data,lvl) set ok=1 } catch ex { set ok=0 }"
+        quit $select(ok:"",1:"FAIL")
+        ;
+irisD(fn,data,out)      ; IRIS decompress via the Python helper fn(data).
+        ; doc: @internal
+        ; doc: "" on success, "FAIL" if Python raised (corrupt input). Same
+        ; doc: ObjectScript try/catch rationale as irisC.
+        new ok
+        if fn="" quit "FAIL"
+        set ok=0
+        xecute "try { do irisInit^STDCOMPRESS() set out=##class(%SYS.Python).Import(""__main__"")."_fn_"(data) set ok=1 } catch ex { set ok=0 }"
+        quit $select(ok:"",1:"FAIL")
+        ;
diff --git a/src/STDCRYPTO.m b/src/STDCRYPTO.m
index 6e25d67..1b46bf5 100644
--- a/src/STDCRYPTO.m
+++ b/src/STDCRYPTO.m
@@ -36,10 +36,14 @@
         ;   $$available^STDCRYPTO()               — 1 iff stdcrypto callout
         ;                                            is loaded
         ;
-        ; Backend: $&stdcrypto.<fn> → libcrypto (OpenSSL EVP_Digest + HMAC).
-        ; The C source is at src/callouts/std_crypto.c; the YDB call-out
-        ; descriptor is at tools/std_crypto.xc; the build harness is
-        ; tools/build-callouts.sh.
+        ; Backend (engine-branched in dispatch3 / dispatch4 on $zversion["IRIS"):
+        ;   YottaDB: $&stdcrypto.<fn> → libcrypto (OpenSSL EVP_Digest + HMAC).
+        ;            C source src/callouts/std_crypto.c; descriptor
+        ;            tools/std_crypto.xc; built by tools/build-callouts.sh.
+        ;   IRIS:    $SYSTEM.Encryption.SHAHash / .HMACSHA (built-in classes;
+        ;            no callout, no .so). Same raw-byte digest output, so the
+        ;            public hex/Bytes API and the *TST.m vectors are identical
+        ;            on both engines.
         ;
         ; YottaDB ABI note — argc-prefixed C signatures: YDB's
         ; $&pkg.fn(args) external-call ABI prepends an `int argc` to
@@ -267,7 +271,9 @@
 dispatch3(sym,inp,out,isDigest) ; Invoke $&stdcrypto.<sym>(inp,.out).
         ; doc: @internal
         ; doc: Wraps $& in an XECUTE'd command string. Returns 1 on
-        ; doc: success, 0 on failure with $ECODE set.
+        ; doc: success, 0 on failure with $ECODE set. On IRIS, branches to
+        ; doc: irisDigest ($SYSTEM.Encryption.SHAHash) instead of the YDB callout.
+        if $zversion["IRIS" quit $$irisDigest(sym,inp,.out)
         new $etrap,rc,cmd
         set $etrap="set $ecode="""" set rc=-1 quit -1"
         set rc=0
@@ -281,7 +287,9 @@
         ;
 dispatch4(sym,key,msg,out)      ; Invoke $&stdcrypto.<sym>(key,msg,.out).
         ; doc: @internal
-        ; doc: Same XECUTE-wrap rationale as dispatch3.
+        ; doc: Same XECUTE-wrap rationale as dispatch3. On IRIS, branches to
+        ; doc: irisHmac ($SYSTEM.Encryption.HMACSHA) instead of the YDB callout.
+        if $zversion["IRIS" quit $$irisHmac(sym,key,msg,.out)
         new $etrap,rc,cmd
         set $etrap="set $ecode="""" set rc=-1 quit -1"
         set rc=0
@@ -292,6 +300,40 @@
         set $ecode=",U-STDCRYPTO-HMAC-FAIL,"
         quit 0
         ;
+        ; ---------- IRIS-native backend ($SYSTEM.Encryption) ----------
+        ; IRIS has no $&pkg.fn callout ABI; it ships SHA / HMAC as built-in
+        ; ObjectScript class methods. The calls are XECUTE-wrapped for the
+        ; same reason as the YDB arm — $SYSTEM.<class>.<method> is not M the
+        ; tree-sitter-m grammar parses, so it must live inside a string.
+        ; Both produce raw digest bytes, identical to libcrypto's output.
+        ;
+digestBits(sym) ; SHA bit-width implied by sym name (256 / 384 / 512).
+        ; doc: @internal
+        quit $select(sym["512":512,sym["384":384,1:256)
+        ;
+irisDigest(sym,inp,out) ; IRIS SHA digest into out via $SYSTEM.Encryption.SHAHash.
+        ; doc: @internal
+        ; doc: Returns 1 on success, 0 (with $ECODE) on failure.
+        new $etrap,cmd,bits
+        set $etrap="set $ecode="""" quit 0"
+        set bits=$$digestBits(sym)
+        set cmd="set out=$system.Encryption.SHAHash("_bits_",inp)"
+        xecute cmd
+        if $length($get(out))'=(bits\8) set $ecode=",U-STDCRYPTO-DIGEST-FAIL," quit 0
+        quit 1
+        ;
+irisHmac(sym,key,msg,out)       ; IRIS HMAC into out via $SYSTEM.Encryption.HMACSHA.
+        ; doc: @internal
+        ; doc: Returns 1 on success, 0 (with $ECODE) on failure. Arg order is
+        ; doc: HMACSHA(bits,data,key) — verified against RFC 4231 vectors.
+        new $etrap,cmd,bits
+        set $etrap="set $ecode="""" quit 0"
+        set bits=$$digestBits(sym)
+        set cmd="set out=$system.Encryption.HMACSHA("_bits_",msg,key)"
+        xecute cmd
+        if $length($get(out))'=(bits\8) set $ecode=",U-STDCRYPTO-HMAC-FAIL," quit 0
+        quit 1
+        ;
 zeros(n)        ; n NUL bytes — pre-allocates the O:ydb_string_t* output.
         ; doc: @internal
         ; doc: Pre-allocation for YDB callout output buffers.
diff --git a/src/STDHTTP.m b/src/STDHTTP.m
index f6e2e2e..a42893e 100644
--- a/src/STDHTTP.m
+++ b/src/STDHTTP.m
@@ -316,7 +316,9 @@ set resp("body")=respBody
         ; doc: @since         v0.4.0
         ; doc: @stable        stable
         ; doc: @see           $$request^STDHTTP
-        ; doc: Never raises — clears $ECODE on the way out.
+        ; doc: Never raises — clears $ECODE on the way out. On IRIS the HTTP
+        ; doc: backend is the built-in %Net.HttpRequest class, always present.
+        if $zversion["IRIS" quit 1
         new $etrap,rc,cmd
         if $$env^STDOS("ydb_xc_stdhttp")="" quit 0
         set $etrap="set $ecode="""" set rc=0 quit 0"
@@ -368,7 +370,9 @@ set resp("body")=respBody
 dispatchPerform(method,url,headerBlock,body,timeoutMs,follow,verify,statusCode,respHeaders,respBody,errMsg)      ; Invoke $&stdhttp.http_perform(...).
         ; doc: @internal
         ; doc: XECUTE-wraps the namespaced $&pkg.fn call. Returns the
-        ; doc: C-side rc on success, -99 if the callout is unavailable.
+        ; doc: C-side rc on success, -99 if the callout is unavailable. On IRIS
+        ; doc: it dispatches to irisPerform (%Net.HttpRequest) instead.
+        if $zversion["IRIS" quit $$irisPerform(method,url,headerBlock,body,timeoutMs,follow,verify,.statusCode,.respHeaders,.respBody,.errMsg)
         new $etrap,rc,cmd
         if $$env^STDOS("ydb_xc_stdhttp")="" quit -99
         set $etrap="set $ecode="""" set rc=-99 quit -99"
@@ -378,3 +382,49 @@ set resp("body")=respBody
         set $ecode=""
         quit rc
         ;
+        ; ---------- IRIS-native backend (%Net.HttpRequest) ----------
+        ; IRIS has no $&pkg.fn / libcurl callout; it ships a built-in HTTP/1.1
+        ; client. The OREF / ##class syntax is XECUTE-wrapped (same rationale as
+        ; the $& wrap) so tree-sitter-m never parses it. The request object REQ
+        ; and send-status HSC persist across the XECUTE'd statements via the
+        ; shared symbol table. Output (statusCode/respHeaders/respBody/errMsg)
+        ; mirrors the libcurl contract so request^STDHTTP parses both engines
+        ; identically: respHeaders is rebuilt as a "StatusLine CRLF headers
+        ; CRLFCRLF" block for parseHeaderStream.
+        ;
+irisPerform(method,url,headerBlock,body,timeoutMs,follow,verify,statusCode,respHeaders,respBody,errMsg)  ; IRIS HTTP via %Net.HttpRequest.
+        ; doc: @internal
+        new parts,host,port,https,target,ok,i,line,nm,vl,nl,hk,REQ,HSC
+        set statusCode=0,respHeaders="",respBody="",errMsg=""
+        do parse^STDURL(url,.parts)
+        set host=$get(parts("host")),port=+$get(parts("port")),target=$$requestTarget(.parts)
+        set https=$select($get(parts("scheme"))="https":1,1:0)
+        if 'port set port=$select(https:443,1:80)
+        ; Create + configure the request object (REQ persists across XECUTEs).
+        set ok=0
+        xecute "try { set REQ=##class(%Net.HttpRequest).%New() set REQ.Server=host,REQ.Port=port,REQ.Https=https,REQ.Timeout=$select(timeoutMs>999:timeoutMs\1000,1:1) set ok=1 } catch e { set errMsg=$zerror set ok=0 }"
+        if 'ok set:errMsg="" errMsg="STDHTTP-IRIS-INIT-FAIL" quit 7
+        ; Request headers — split the CRLF block into "Name: value" lines.
+        set nl=$char(13,10)
+        for i=1:1:$length(headerBlock,nl) do
+        . set line=$piece(headerBlock,nl,i) quit:line=""
+        . set nm=$piece(line,":",1),vl=$piece(line,":",2,$length(line,":"))
+        . if $extract(vl)=" " set vl=$extract(vl,2,$length(vl))
+        . xecute "do REQ.SetHeader(nm,vl)"
+        ; Request body.
+        if $length(body) xecute "do REQ.EntityBody.Write(body)"
+        ; Send — Send() returns an error %Status (no throw) on DNS/TCP/TLS fail.
+        set ok=0
+        xecute "try { set HSC=REQ.Send(method,target) set ok=##class(%SYSTEM.Status).IsOK(HSC) } catch e { set ok=0,HSC="""",errMsg=$zerror }"
+        if 'ok do  quit 7
+        . if $get(HSC)'="" xecute "set errMsg=$piece(##class(%SYSTEM.Status).GetErrorText(HSC),$char(13,10),1)"
+        . set:$get(errMsg)="" errMsg="STDHTTP-IRIS-SEND-FAIL"
+        ; Success — status, body, and a reconstructed header block.
+        xecute "set statusCode=REQ.HttpResponse.StatusCode"
+        xecute "set respBody=REQ.HttpResponse.Data.Read($select(REQ.HttpResponse.Data.Size>0:REQ.HttpResponse.Data.Size,1:1))"
+        xecute "set respHeaders=REQ.HttpResponse.StatusLine_nl"
+        set hk=""
+        for  xecute "set hk=$order(REQ.HttpResponse.Headers(hk))" quit:hk=""  xecute "set respHeaders=respHeaders_hk_"": ""_REQ.HttpResponse.GetHeader(hk)_nl"
+        set respHeaders=respHeaders_nl
+        quit 0
+        ;
diff --git a/tests/STDCOMPRESSTST.m b/tests/STDCOMPRESSTST.m
index 9847730..5706008 100644
--- a/tests/STDCOMPRESSTST.m
+++ b/tests/STDCOMPRESSTST.m
@@ -39,10 +39,13 @@
         ; ---- helpers ----
         ;
 mkBinary(n)     ; Build an n-byte string of bytes 0..255 cycling.
-        ; doc: $ZCHAR for byte semantics regardless of $ZCHSET.
+        ; doc: $CHAR is byte-exact under YDB byte mode (ydb_chset=M, the
+        ; doc: contract for these suites) and on IRIS (codepoint==byte for
+        ; doc: 0..255), so the suite is engine-portable. $ZCHAR would be
+        ; doc: YDB-only and breaks IRIS parsing (<SYNTAX>).
         new s,i
         set s=""
-        for i=0:1:n-1 set s=s_$zchar(i#256)
+        for i=0:1:n-1 set s=s_$char(i#256)
         quit s
         ;
 mkRepeated(unit,times)  ; Build unit repeated `times` times — highly compressible.
@@ -63,8 +66,8 @@
         new buf,ok
         set ok=$$gzip^STDCOMPRESS("hello",.buf)
         do true^STDASSERT(.pass,.fail,ok,"gzip succeeded")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,1)),31,"byte 1 = 0x1F")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,2)),139,"byte 2 = 0x8B")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,1)),31,"byte 1 = 0x1F")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,2)),139,"byte 2 = 0x8B")
         quit
         ;
 tGzipRoundTripAscii(pass,fail)  ;@TEST "gzip -> gunzip round-trips an ASCII string"
@@ -149,7 +152,7 @@
         quit
         ;
 tInflateRejectsGarbage(pass,fail)       ;@TEST "inflate() of garbage bytes raises LIBZ-FAIL"
-        do raises^STDASSERT(.pass,.fail,"new raw set raw=$$inflate^STDCOMPRESS($zchar(0,0,0,0,0),.raw)","LIBZ-FAIL","garbage raises LIBZ-FAIL")
+        do raises^STDASSERT(.pass,.fail,"new raw set raw=$$inflate^STDCOMPRESS($char(0,0,0,0,0),.raw)","LIBZ-FAIL","garbage raises LIBZ-FAIL")
         quit
         ;
         ; ---- zstd ----
@@ -158,10 +161,10 @@
         new buf,ok
         set ok=$$zstdCompress^STDCOMPRESS("hello",.buf)
         do true^STDASSERT(.pass,.fail,ok,"zstd compress succeeded")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,1)),40,"byte 1 = 0x28")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,2)),181,"byte 2 = 0xB5")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,3)),47,"byte 3 = 0x2F")
-        do eq^STDASSERT(.pass,.fail,$zascii($extract(buf,4)),253,"byte 4 = 0xFD")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,1)),40,"byte 1 = 0x28")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,2)),181,"byte 2 = 0xB5")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,3)),47,"byte 3 = 0x2F")
+        do eq^STDASSERT(.pass,.fail,$ascii($extract(buf,4)),253,"byte 4 = 0xFD")
         quit
         ;
 tZstdRoundTripAscii(pass,fail)  ;@TEST "zstdCompress -> zstdDecompress round-trips ASCII"