**Stacked on top of #19960.**
## Summary
- `execute_tool` used to check `directTools[toolName]` first, falling
back to the registry. Same tool name, different wrapping: preloaded went
through `wrapToolsWithOutputSerialization`, fallback didn't. Silent
divergence — a model calling a CRUD tool via
\`learn_tools\`/\`execute_tool\` got raw output, while calling it as a
preloaded direct tool got compacted output.
- Now: `execute_tool` always routes through
`toolRegistry.resolveAndExecute`. One path, no fast-path.
- Output serialization (`compactToolOutput`) moves into the registry,
gated by a new `serializeOutput` flag on `hydrateToolSet` /
`resolveAndExecute` / `getToolsByName` / `getToolsByCategories` /
`ToolRetrievalOptions`. Chat passes `true`, MCP and workflow pass
`false`.
## Key changes
**Registry (`tool-registry.service.ts`)**
- `hydrateToolSet` options gain `serializeOutput?: boolean`; when true
the execute closure wraps dispatch result with `compactToolOutput`.
- `resolveAndExecute` signature: replaces unused \`_options:
ToolExecutionOptions\` with `{ serializeOutput?: boolean }`.
- `getToolsByName` and `getToolsByCategories` thread `serializeOutput`
through to `hydrateToolSet`.
**Meta-tool (`execute-tool.tool.ts`)**
- API changes from positional `(toolRegistry, context, directTools?,
excludeTools?)` to `(toolRegistry, context, options?: { excludeTools?,
serializeOutput? })`.
- `directTools` fallback removed. All invocations go to the registry.
**Chat (`chat-execution.service.ts`)**
- Passes `serializeOutput: true` to `getToolsByName` — preloaded tools
get compacted output from the hydrator, no external wrap needed.
- Drops the external `wrapToolsWithOutputSerialization(preloadedTools)`
call.
- `createExecuteToolTool` call now passes `{ serializeOutput: true }`.
Direct-tool and `execute_tool` paths produce identical output shape.
**MCP (`mcp-protocol.service.ts`)**
- `createExecuteToolTool` call updated to new options shape with `{
excludeTools: MCP_EXCLUDED_TOOLS }`. No `serializeOutput` flag → raw
output as today.
**Deletes**
- `output-serialization/wrap-tools-with-output-serialization.util.ts` —
sole caller removed.
## Behavior changes
- **Chat, `execute_tool` fallback path**: now produces compacted output
(matches direct path). Net effect: fewer tokens for CRUD results reached
via discovery. Intended improvement.
- **Chat, `execute_tool({toolName: 'web_search'})` edge**: today
silently hits the native tool via `directTools`; now returns \"tool not
found, use get_tool_catalog\". Self-correcting, rare — native tools are
always directly available to the model.
- **MCP**: no change. No `serializeOutput` flag → identical raw output.
- **Workflow agent**: no change. Doesn't use `execute_tool`.
## Test plan
- [ ] `npx nx typecheck twenty-server` passes (verified: 7 pre-existing
unrelated errors, zero new)
- [ ] \`npx jest
packages/twenty-server/src/engine/api/mcp/services/__tests__/mcp-protocol.service.spec.ts\`
passes in CI
- [ ] AI chat: call a preloaded tool (e.g. \`search_help_center\`)
directly → compacted output
- [ ] AI chat: call a non-preloaded CRUD tool via
\`learn_tools\`/\`execute_tool\` → compacted output (this is the
behavior change)
- [ ] AI chat: native \`web_search\` still works when model calls it
directly
- [ ] MCP: \`tools/call\` on a registry tool → raw output (nulls
preserved)
- [ ] Workflow AI agent: tool dispatch unchanged
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
