refactor(frontend): decompose sessions.js tool rendering into dispatc…

docs/architecture.md

@@ -105,10 +105,13 @@ The UI is a **hash-routed** SPA with ES modules under `static/js/`:
 
 - `app.js` — routing and boot
 - `projects.js`, `sessions.js`, `search.js`, `export.js` — route handlers
+- `render/registry.js` — **tool dispatch registry** for session UI: `TOOL_USE_RENDERERS` and `TOOL_RESULT_RENDERERS` map tool name / `result_type` → render function (one module per type under `render/tool_use/` and `render/tool_result/`). Parallels backend `utils/tool_dispatch.py` (backend uses ordered predicates; frontend uses direct key lookup + fallback).
 - `shared/markdown.js` — markdown + **DOMPurify** sanitization (do not render raw LLM HTML)
 - `shared/state.js`, `shared/utils.js`, `shared/theme.js` — shared UI state and helpers
 
-No bundler step — modern browsers load modules directly. Frontend unit tests use **vitest** + **jsdom** (`npm test`).
+`sessions.js` keeps workspace/session orchestration and message bubbles; tool cards delegate to `render/registry.js`.
+
+No bundler step — modern browsers load modules directly. Frontend unit tests use **vitest** + **jsdom** (`npm test`), including `static/js/render/registry.test.js` for registry wiring and renderer escaping.
 
 ## Continuous integration
 

static/js/render/constants.js

@@ -0,0 +1,5 @@
+/**
+ * Sentinel when tool.name or result_type is missing.
+ * Used for fallback routing only — do not add UNKNOWN_DISPATCH_KEY to TOOL_*_RENDERERS.
+ */
+export const UNKNOWN_DISPATCH_KEY = 'unknown';

static/js/render/registry.js

@@ -0,0 +1,84 @@
+import { renderBashUse } from './tool_use/bash.js';
+import { renderReadUse } from './tool_use/read.js';
+import { renderWriteUse } from './tool_use/write.js';
+import { renderEditUse } from './tool_use/edit.js';
+import { renderGlobUse } from './tool_use/glob.js';
+import { renderGrepUse } from './tool_use/grep.js';
+import { renderTaskUse } from './tool_use/task.js';
+import { renderTodoWriteUse } from './tool_use/todo_write.js';
+import { renderAskUserQuestionUse } from './tool_use/ask_user_question.js';
+import { renderWebFetchUse } from './tool_use/web_fetch.js';
+import { renderWebSearchUse } from './tool_use/web_search.js';
+import { renderToolUseFallback } from './tool_use/fallback.js';
+import { getToolSummary } from './tool_use/summary.js';
+import { UNKNOWN_DISPATCH_KEY } from './constants.js';
+
+import { renderBashResult } from './tool_result/bash.js';
+import { renderFileReadResult } from './tool_result/file_read.js';
+import { renderFileEditResult } from './tool_result/file_edit.js';
+import { renderFileWriteResult } from './tool_result/file_write.js';
+import { renderGlobResult } from './tool_result/glob.js';
+import { renderGrepResult } from './tool_result/grep.js';
+import { renderWebSearchResult } from './tool_result/web_search.js';
+import { renderWebFetchResult } from './tool_result/web_fetch.js';
+import { renderTaskResult } from './tool_result/task.js';
+import { renderTodoWriteResult } from './tool_result/todo_write.js';
+import { renderUserInputResult } from './tool_result/user_input.js';
+import { renderPlanResult } from './tool_result/plan.js';
+import { renderToolResultFallback } from './tool_result/fallback.js';
+import { toolResultHasBody } from './tool_result/utils.js';
+
+export { getToolSummary, toolResultHasBody };
+
+export const TOOL_USE_RENDERERS = {
+    Bash: renderBashUse,
+    Read: renderReadUse,
+    Write: renderWriteUse,
+    Edit: renderEditUse,
+    Glob: renderGlobUse,
+    Grep: renderGrepUse,
+    Task: renderTaskUse,
+    TodoWrite: renderTodoWriteUse,
+    AskUserQuestion: renderAskUserQuestionUse,
+    WebFetch: renderWebFetchUse,
+    WebSearch: renderWebSearchUse,
+};
+
+export const TOOL_RESULT_RENDERERS = {
+    bash: renderBashResult,
+    file_read: renderFileReadResult,
+    file_edit: renderFileEditResult,
+    file_write: renderFileWriteResult,
+    glob: renderGlobResult,
+    grep: renderGrepResult,
+    web_search: renderWebSearchResult,
+    web_fetch: renderWebFetchResult,
+    task: renderTaskResult,
+    todo_write: renderTodoWriteResult,
+    user_input: renderUserInputResult,
+    plan: renderPlanResult,
+};
+
+function getToolUseRenderer(name) {
+    return Object.prototype.hasOwnProperty.call(TOOL_USE_RENDERERS, name)
+        ? TOOL_USE_RENDERERS[name]
+        : renderToolUseFallback;
+}
+
+function getToolResultRenderer(resultType) {
+    return Object.prototype.hasOwnProperty.call(TOOL_RESULT_RENDERERS, resultType)
+        ? TOOL_RESULT_RENDERERS[resultType]
+        : renderToolResultFallback;
+}
+
+export function renderToolUse(tool) {
+    if (!tool) return '';
+    const name = tool.name || UNKNOWN_DISPATCH_KEY;
+    return getToolUseRenderer(name)(tool);
+}
+
+export function renderToolResult(parsed) {
+    if (!parsed) return '';
+    const rt = parsed.result_type || UNKNOWN_DISPATCH_KEY;
+    return getToolResultRenderer(rt)(parsed);
+}

static/js/render/registry.test.js

@@ -0,0 +1,203 @@
+import { describe, it, expect } from 'vitest';
+import {
+    TOOL_USE_RENDERERS,
+    TOOL_RESULT_RENDERERS,
+    renderToolUse,
+    renderToolResult,
+    getToolSummary,
+    toolResultHasBody,
+} from './registry.js';
+import { UNKNOWN_DISPATCH_KEY } from './constants.js';
+import { renderWebFetchUse } from './tool_use/web_fetch.js';
+
+const CORE_TOOL_USE = ['Bash', 'Read', 'Write', 'Edit', 'Glob', 'Grep', 'Task', 'TodoWrite', 'AskUserQuestion', 'WebFetch', 'WebSearch'];
+
+const CORE_TOOL_RESULT = [
+    'bash',
+    'file_read',
+    'file_edit',
+    'file_write',
+    'glob',
+    'grep',
+    'web_search',
+    'web_fetch',
+    'task',
+    'todo_write',
+    'user_input',
+    'plan',
+];
+
+describe('TOOL_USE_RENDERERS', () => {
+    it('registers core tool names', () => {
+        for (const name of CORE_TOOL_USE) {
+            expect(TOOL_USE_RENDERERS[name], name).toBeTypeOf('function');
+        }
+    });
+
+    it('does not register the unknown dispatch sentinel as a tool renderer', () => {
+        expect(Object.prototype.hasOwnProperty.call(TOOL_USE_RENDERERS, UNKNOWN_DISPATCH_KEY)).toBe(false);
+    });
+
+    it('renderBashUse escapes HTML in command', () => {
+        const html = renderToolUse({
+            name: 'Bash',
+            input: { command: '<script>alert(1)</script>' },
+        });
+        expect(html).not.toContain('<script>');
+        expect(html).toContain('&lt;script&gt;');
+    });
+
+    it('returns empty string for null or undefined tool', () => {
+        expect(renderToolUse(null)).toBe('');
+        expect(renderToolUse(undefined)).toBe('');
+    });
+
+    it('renderReadUse escapes file path in body and summary', () => {
+        const html = renderToolUse({
+            name: 'Read',
+            input: { file_path: 'C:\\tmp\\<evil>.txt' },
+        });
+        expect(html).toContain('&lt;evil&gt;');
+        expect(html).not.toContain('<evil>');
+    });
+});
+
+describe('TOOL_RESULT_RENDERERS', () => {
+    it('registers core result types', () => {
+        for (const rt of CORE_TOOL_RESULT) {
+            expect(TOOL_RESULT_RENDERERS[rt], rt).toBeTypeOf('function');
+        }
+    });
+
+    it('renderBashResult escapes stdout', () => {
+        const html = renderToolResult({
+            result_type: 'bash',
+            exit_code: 0,
+            stdout: '<img onerror=alert(1)>',
+        });
+        expect(html).not.toContain('<img');
+        expect(html).toContain('&lt;img');
+    });
+
+    it('renderBashResult avoids undefined in summary when exit_code missing', () => {
+        const html = renderToolResult({ result_type: 'bash' });
+        expect(html).toContain('Bash Result (unknown)');
+        expect(html).not.toContain('undefined');
+    });
+
+    it('returns empty string for null or undefined parsed', () => {
+        expect(renderToolResult(null)).toBe('');
+        expect(renderToolResult(undefined)).toBe('');
+    });
+});
+
+describe('toolResultHasBody', () => {
+    it('returns false for null or undefined', () => {
+        expect(toolResultHasBody(null)).toBe(false);
+        expect(toolResultHasBody(undefined)).toBe(false);
+    });
+
+    it('returns true for bash with stdout or stderr', () => {
+        expect(toolResultHasBody({ result_type: 'bash', stdout: 'ok' })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'bash', stderr: 'err' })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'bash' })).toBe(false);
+    });
+
+    it('returns false for summary-only result types', () => {
+        expect(toolResultHasBody({ result_type: 'file_read', file_path: '/a' })).toBe(false);
+        expect(toolResultHasBody({ result_type: 'glob', num_files: 3 })).toBe(false);
+    });
+
+    it('returns true for user_input and todo_write with todos', () => {
+        expect(toolResultHasBody({ result_type: 'user_input' })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'todo_write', todos: [{ content: 'x' }] })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'todo_write', todo_count: 1 })).toBe(false);
+    });
+
+    it('returns true for task when duration, retrieval, or description is set', () => {
+        expect(toolResultHasBody({ result_type: 'task', description: 'subagent' })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'task', total_duration_ms: 100 })).toBe(true);
+        expect(toolResultHasBody({ result_type: 'task', status: 'completed' })).toBe(false);
+    });
+});
+
+describe('getToolSummary', () => {
+    it('formats Bash summary', () => {
+        expect(getToolSummary('Bash', { command: 'ls -la' })).toMatch(/Bash:/);
+        expect(getToolSummary('Bash', { command: 'ls -la' })).toContain('ls -la');
+    });
+
+    it('formats Read summary as plain text (escaping deferred to wrapToolUse)', () => {
+        expect(getToolSummary('Read', { file_path: 'a<b' })).toBe('Read: a<b');
+    });
+});
+
+describe('renderToolUse fallback', () => {
+    it('uses JSON fallback for unknown tools', () => {
+        const html = renderToolUse({
+            name: 'UnknownToolXYZ',
+            input: { foo: 'bar' },
+        });
+        expect(html).toContain('tool-call');
+        expect(html).toContain('&quot;foo&quot;');
+        expect(TOOL_USE_RENDERERS.UnknownToolXYZ).toBeUndefined();
+    });
+
+    it('uses fallback when name is an inherited property (e.g. constructor)', () => {
+        const html = renderToolUse({
+            name: 'constructor',
+            input: { foo: 'bar' },
+        });
+        expect(html).toContain('tool-call');
+        expect(html).toContain('&quot;foo&quot;');
+    });
+
+    it('dispatches WebFetch to registered renderer (not generic unknown-tool fallback)', () => {
+        expect(TOOL_USE_RENDERERS.WebFetch).toBe(renderWebFetchUse);
+        const html = renderToolUse({
+            name: 'WebFetch',
+            input: { url: 'https://example.com' },
+        });
+        expect(html).toContain('tool-call');
+        expect(html).toContain('example.com');
+    });
+
+    it('renders WebSearch via registry', () => {
+        const html = renderToolUse({
+            name: 'WebSearch',
+            input: { query: 'vitest registry' },
+        });
+        expect(html).toContain('tool-call');
+        expect(html).toContain('vitest registry');
+    });
+});
+
+describe('renderTodoWriteResult', () => {
+    it('summary count matches parsed.todos length when todos are present', () => {
+        const html = renderToolResult({
+            result_type: 'todo_write',
+            todo_count: 99,
+            todos: [
+                { status: 'pending', content: 'one' },
+                { status: 'completed', content: 'two' },
+            ],
+        });
+        expect(html).toContain('Todos updated (2 items)');
+        expect(html).not.toContain('99 items');
+    });
+});
+
+describe('renderToolResult fallback', () => {
+    it('renders summary-only for unknown result types', () => {
+        const html = renderToolResult({ result_type: 'custom_type' });
+        expect(html).toContain('Tool result (custom_type)');
+        expect(html).toContain('tool-result');
+    });
+
+    it('uses fallback when result_type is an inherited property (e.g. constructor)', () => {
+        const html = renderToolResult({ result_type: 'constructor' });
+        expect(html).toContain('Tool result (constructor)');
+        expect(html).toContain('tool-result');
+        expect(Object.prototype.hasOwnProperty.call(TOOL_RESULT_RENDERERS, 'constructor')).toBe(false);
+    });
+});

static/js/render/tool_result/bash.js

@@ -0,0 +1,23 @@
+import { esc, truncate } from '../../shared/utils.js';
+import { finishToolResult } from './common.js';
+
+export function renderBashResult(parsed) {
+    const exitCode = parsed.exit_code;
+    let status;
+    if (parsed.interrupted) {
+        status = 'interrupted';
+    } else if (parsed.is_error) {
+        status = typeof exitCode === 'number' ? `error (exit ${exitCode})` : 'error';
+    } else if (exitCode === 0) {
+        status = 'success';
+    } else if (typeof exitCode === 'number') {
+        status = `exit ${exitCode}`;
+    } else {
+        status = 'unknown';
+    }
+    const summary = `Bash Result (${status})`;
+    let body = '';
+    if (parsed.stdout) body += `<div class="tool-call-section"><div class="tool-call-section-title">stdout</div><pre><code>${esc(truncate(parsed.stdout, 2000))}</code></pre></div>`;
+    if (parsed.stderr) body += `<div class="tool-call-section"><div class="tool-call-section-title">stderr</div><pre style="border-left:3px solid var(--danger)"><code>${esc(truncate(parsed.stderr, 1000))}</code></pre></div>`;
+    return finishToolResult(summary, body);
+}

static/js/render/tool_result/common.js

@@ -0,0 +1,8 @@
+import { esc } from '../../shared/utils.js';
+
+export function finishToolResult(summary, body) {
+    if (!body) {
+        return `<div class="tool-result"><span class="tool-result-summary">${esc(summary)}</span></div>`;
+    }
+    return `<details class="tool-result"><summary class="tool-result-summary">${esc(summary)}</summary><div class="tool-call-body">${body}</div></details>`;
+}

static/js/render/tool_result/fallback.js

@@ -0,0 +1,8 @@
+import { finishToolResult } from './common.js';
+import { UNKNOWN_DISPATCH_KEY } from '../constants.js';
+
+export function renderToolResultFallback(parsed) {
+    const rt = parsed.result_type || UNKNOWN_DISPATCH_KEY;
+    const summary = `Tool result (${rt})`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/file_edit.js

@@ -0,0 +1,6 @@
+import { finishToolResult } from './common.js';
+
+export function renderFileEditResult(parsed) {
+    const summary = `Edited: ${parsed.file_path || ''}`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/file_read.js

@@ -0,0 +1,7 @@
+import { finishToolResult } from './common.js';
+
+export function renderFileReadResult(parsed) {
+    const numLines = parsed.num_lines ? ` (${parsed.num_lines} lines)` : '';
+    const summary = `Read: ${parsed.file_path || ''}${numLines}`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/file_write.js

@@ -0,0 +1,6 @@
+import { finishToolResult } from './common.js';
+
+export function renderFileWriteResult(parsed) {
+    const summary = `Wrote: ${parsed.file_path || ''}`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/glob.js

@@ -0,0 +1,7 @@
+import { finishToolResult } from './common.js';
+
+export function renderGlobResult(parsed) {
+    const trunc = parsed.truncated ? ' (truncated)' : '';
+    const summary = `Glob: ${parsed.num_files || 0} files found${trunc}`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/grep.js

@@ -0,0 +1,6 @@
+import { finishToolResult } from './common.js';
+
+export function renderGrepResult(parsed) {
+    const summary = `Grep: ${parsed.num_files || 0} files, ${parsed.num_lines || 0} lines`;
+    return finishToolResult(summary, '');
+}

static/js/render/tool_result/plan.js

@@ -0,0 +1,6 @@
+import { finishToolResult } from './common.js';
+
+export function renderPlanResult(parsed) {
+    const summary = `Plan: ${parsed.file_path || ''}`;
+    return finishToolResult(summary, '');
+}