The invalid-params error paths already listed available agents,
but the unknown-agent path in runSingleAgent just returned
'Unknown agent: claude' with no hint what exists.
Now: 'Unknown agent: "claude". Available agents: "worker".'
Model would guess names like "claude", "default", or skill names
like "brave-search". Now it self-corrects on the next call.
Tested with Opus 4.6: without fix, model gave up on subagent
and ran the tool calls itself instead. With fix, 1 wasted call.
BREAKING CHANGE: ToolDefinition.execute parameter order changed from
(id, params, onUpdate, ctx, signal) to (id, params, signal, onUpdate, ctx).
This aligns with AgentTool.execute so wrapping built-in tools no longer
requires parameter reordering. Update extensions by swapping signal and
onUpdate parameters.
Breaking changes:
- Settings: 'hooks' and 'customTools' arrays replaced with 'extensions'
- CLI: '--hook' and '--tool' flags replaced with '--extension' / '-e'
- API: HookMessage renamed to CustomMessage, role 'hookMessage' to 'custom'
- API: FileSlashCommand renamed to PromptTemplate
- API: discoverSlashCommands() renamed to discoverPromptTemplates()
- Directories: commands/ renamed to prompts/ for prompt templates
Migration:
- Session version bumped to 3 (auto-migrates v2 sessions)
- Old 'hookMessage' role entries converted to 'custom'
Structural changes:
- src/core/hooks/ and src/core/custom-tools/ merged into src/core/extensions/
- src/core/slash-commands.ts renamed to src/core/prompt-templates.ts
- examples/hooks/ and examples/custom-tools/ merged into examples/extensions/
- docs/hooks.md and docs/custom-tools.md merged into docs/extensions.md
New test coverage:
- test/extensions-runner.test.ts (10 tests)
- test/extensions-discovery.test.ts (26 tests)
- test/prompt-templates.test.ts
