Handle empty Antigravity print results

README.md

@@ -49,6 +49,11 @@ What is stable today:
 - Antigravity can be launched through the unattended `agy --print` route.
 - Antigravity receives a narrow task handoff and reports back through a tiny
   report-only MCP server.
+- `agy --print` stdout is diagnostic only. Planner/tool-call streams may exit
+  successfully with empty stdout, so the closed-loop completion signal is the
+  report MCP or result file marker. When local `agy` drops stdout but records the
+  response in its conversation database, Dev Triangle can recover the completion
+  marker from `%USERPROFILE%\.gemini\antigravity-cli\conversations`.
 - The local ledger records jobs, handoffs, statuses, result paths, and notes.
 - CI validates the MCP protocol on Windows and Ubuntu without needing real
   Jules or Antigravity credentials.
@@ -60,6 +65,13 @@ What is intentionally not claimed:
 - This does not store Jules secrets for you.
 - The older Antigravity IDE chat launch path can open a UI, but the stable
   unattended path is `agy --print`.
+- Do not hard-code an Antigravity model label unless it has been verified on the
+  local machine. If `ANTIGRAVITY_AGY_MODEL` is unset, Dev Triangle lets `agy`
+  choose its own default model.
+- Dev Triangle ignores the legacy unsafe `Gemini 3.5 Flash (Medium)` value even
+  if it is inherited from the parent process environment.
+- New installs should not set `ANTIGRAVITY_AGY_MODEL` by default. Leave model
+  choice to `agy` unless a local model label has been verified on that machine.
 - CI uses deterministic fake worker paths. Real local Antigravity validation is
   covered by `scripts/demo-user-flow.ps1` on a machine with `agy` installed.
 

config/codex.config.toml

@@ -26,5 +26,4 @@ ANTIGRAVITY_HANDOFF_DIR = "C:\\Users\\you\\.dev-triangle\\antigravity-handoffs"
 ANTIGRAVITY_EXECUTION_STYLE = "auto"
 ANTIGRAVITY_CHAT_MODE = "agent"
 ANTIGRAVITY_WINDOW_MODE = "new"
-ANTIGRAVITY_AGY_MODEL = "Gemini 3.5 Flash (Medium)"
 ANTIGRAVITY_AGY_PRINT_TIMEOUT = "30m"

docs/TOOL_REFERENCE.md

@@ -238,6 +238,22 @@ On many Windows installs, the resolved path is:
 
 Use this before trying to run a real handoff.
 
+Optional diagnostics:
+
+- `smokePrint`: runs a short `agy --print` smoke.
+- `smokeTimeoutSec`: timeout for that smoke.
+
+The smoke is diagnostic. Some Antigravity planner/tool-call streams can exit
+with empty stdout, so a failed print smoke does not mean `agy` is missing; it
+means headless completion capture needs the result mailbox/report MCP path.
+If the environment contains the legacy unsafe `Gemini 3.5 Flash (Medium)`
+model value, Dev Triangle ignores it and reports that through `agyModelNote`.
+When stdout is empty but the model response is stored in the Antigravity
+conversation SQLite database, Dev Triangle checks the recent databases under
+`%USERPROFILE%\.gemini\antigravity-cli\conversations` and can mark the smoke
+passed from that fallback. Set `ANTIGRAVITY_AGY_CONVERSATION_DIR` only when a
+test or custom install stores those databases elsewhere.
+
 ### `run_antigravity_handoff`
 
 Runs a prepared handoff through Antigravity CLI.
@@ -253,11 +269,21 @@ Useful options:
 - `dryRun`: builds the command without launching Antigravity.
 - `waitForResult`: waits for the closed-loop result.
 - `resultTimeoutSec`: how long to wait for the result marker.
+- `emptyStdoutResultGraceSec`: short grace wait when `agy --print` exits 0 with
+  empty stdout and no result file.
 - `pollIntervalSec`: how often to check for the result.
 
 The command is considered fully complete when the result path is ready and the
 marker is present.
 
+If `agy --print` exits 0 but stdout is empty and no result appears, the handoff
+is marked `DEGRADED_NO_RESULT`. Treat stdout as diagnostic only; use
+`complete_dev_triangle_handoff` or the result marker as the completion signal.
+Before returning `DEGRADED_NO_RESULT`, Dev Triangle also checks recent
+Antigravity conversation databases for `DEV_TRIANGLE_RESULT_READY`. If the
+marker is found in a non-user response step, the server writes the recovered
+content to the result path and marks the handoff `COMPLETED`.
+
 ### `antigravity_get_result`
 
 Reads or waits for an Antigravity result file.
@@ -282,6 +308,11 @@ reachability, and Antigravity CLI detection.
 
 Use this as the first diagnostic tool.
 
+Optional diagnostics:
+
+- `includeAntigravityPrintSmoke`: run the `agy --print` smoke.
+- `antigravitySmokeTimeoutSec`: timeout for that smoke.
+
 ### `job_list`
 
 Lists local jobs and handoffs from the ledger.

docs/TROUBLESHOOTING.md

@@ -26,6 +26,7 @@ worker still fails, inspect the worker-specific section below.
 | `prepare_jules_repo` is blocked | Secret-looking files, dirty repo, or missing confirmation | Read `safety.blockingFindings`, commit/ignore/remove risky files, then rerun |
 | `agy` not found | Antigravity CLI is missing or not on PATH | Install Antigravity CLI or set `ANTIGRAVITY_COMMAND` |
 | Handoff stuck at `AWAITING_RESULT` | Worker launched but did not submit a report | Check result path, result marker, and Antigravity output |
+| Handoff returns `DEGRADED_NO_RESULT` | `agy --print` exited 0 with empty stdout, no result file, and no recoverable marker in the Antigravity conversation DB | Check report MCP config, result path permissions, and avoid unverified model labels |
 | Result file exists but is not ready | Missing `DEV_TRIANGLE_RESULT_READY` marker | Have the worker submit through `complete_dev_triangle_handoff` |
 | Smoke test passes but real demo fails | Protocol is healthy, real CLI/auth/model path is not | Run `doctor.ps1`, then test `agy --version` and the demo again |
 | CI passes but local worker fails | CI uses fake worker paths | Use `demo-user-flow.ps1` for real local validation |
@@ -171,6 +172,40 @@ Then run:
 .\scripts\doctor.ps1
 ```
 
+### `agy --print` exits 0 but stdout is empty
+
+This can happen even when Antigravity authenticated and hit the model stream.
+The CLI may emit planner or tool-call events without a final printable response.
+Dev Triangle therefore treats stdout as diagnostic only; a handoff is complete
+only when `complete_dev_triangle_handoff` is called or the result file contains
+`DEV_TRIANGLE_RESULT_READY`.
+
+Common causes:
+
+- The worker did not submit through `dev-triangle-report`.
+- The result file was not written under the allowed result directory.
+- `ANTIGRAVITY_AGY_MODEL` names a model label that is not available locally.
+- The agent spent the run planning or calling tools and never produced a final
+  report.
+
+Fixes:
+
+- Leave `ANTIGRAVITY_AGY_MODEL` unset unless you have verified the exact local
+  label.
+- Dev Triangle ignores the legacy unsafe `Gemini 3.5 Flash (Medium)` value even
+  when a parent process still has it in the environment.
+- Run `mcp_health_check` with `includeAntigravityPrintSmoke=true` when you need
+  to diagnose headless output.
+- Prefer the report-only MCP path: `complete_dev_triangle_handoff`.
+- If stdout is empty and no result file appears, Dev Triangle checks recent
+  Antigravity conversation SQLite databases for `DEV_TRIANGLE_RESULT_READY`.
+  Only when the mailbox and database fallback both fail should it report
+  `DEGRADED_NO_RESULT`.
+- If `agy` keeps selecting an unavailable or stale model, open Antigravity once,
+  switch the model in the visible selector, and leave `ANTIGRAVITY_AGY_MODEL`
+  unset. Do not encode a model label in Codex config or install templates unless
+  it has just been verified locally.
+
 ## Handoff Stuck At `AWAITING_RESULT`
 
 This means Dev Triangle MCP created or launched the handoff, but Codex has not

docs/USER_GUIDE.md

@@ -184,6 +184,8 @@ sequenceDiagram
   MCP->>AG: agy --print with handoff prompt
   AG->>Report: complete_dev_triangle_handoff
   Report->>Ledger: write result markdown + update status
+  AG-->>MCP: stdout may be empty
+  MCP->>Ledger: recover marker from Antigravity conversation DB if needed
   Codex->>MCP: antigravity_get_result
   MCP->>Codex: status, result path, report content
   Codex->>User: final explanation
@@ -289,6 +291,10 @@ Then check the result directory:
 If a handoff is stuck at `AWAITING_RESULT`, the worker launched but did not
 write the result marker. See [Troubleshooting](TROUBLESHOOTING.md).
 
+If `agy --print` exits with empty stdout, do not treat stdout as the source of
+truth. The handoff is complete only when the report MCP, result file marker, or
+recoverable Antigravity conversation DB marker proves completion.
+
 ## Human Expectations
 
 Dev Triangle MCP is a coordination layer. It should make the workflow easier to

scripts/install-local.ps1

@@ -208,7 +208,6 @@ ANTIGRAVITY_COMMAND = '$AgyPath'
 ANTIGRAVITY_EXECUTION_STYLE = "auto"
 ANTIGRAVITY_CHAT_MODE = "agent"
 ANTIGRAVITY_WINDOW_MODE = "new"
-ANTIGRAVITY_AGY_MODEL = "Gemini 3.5 Flash (Medium)"
 ANTIGRAVITY_AGY_PRINT_TIMEOUT = "30m"
 "@