Substring-match fixtures (pie chart, bar chart, schedule, trip, etc.)
cross-fired across demos with different tool surfaces and returned tool
names the target agent never registered, causing demos to render nothing
in prod when aimock handles traffic.
Fixture changes (showcase/aimock/feature-parity.json):
- Replace generic pie-chart / bar-chart matches with per-suggestion
specific phrases so gen-ui-tool-based gets render_pie_chart /
render_bar_chart directly and beautiful-chat gets pieChart / barChart
with real data (skipping the query_data two-step that caused the
infinite loop on re-matching prompts).
- Narrow schedule+meeting to the Beautiful Chat 30-minute prompt
returning scheduleTime.
- Narrow flight+fly to flights-from-SFO-to-JFK.
- Narrow background to sunset-themed-gradient.
- Remove trip, sales, pipeline, todo: substring-false-firing across
unrelated demos; interrupt/A2UI demos fall through to real LLM.
Guardrail (showcase/scripts/validate-fixture-tool-surface.ts):
- Pure validate() cross-references every fixture's tool-call name
against the tool surface of each demo whose suggestion prompt contains
the fixture's match substring. Loud failure when the fixture returns a
tool the demo's agent does not register.
- CLI walks packages/ collecting suggestions from page.tsx + hooks/,
frontend tools from useComponent / useHumanInTheLoop / useFrontendTool
/ useRenderTool / useDefaultRenderTool, and backend tools via route.ts
agentId->graphId map + langgraph.json graph->file + @tool decorators.
- 7 vitest cases written TDD-first covering the drift detection,
content-only fixtures, case-insensitivity, and multi-tool responses.
- Current state: 33 fixtures x 191 demos, no drift. Counterfactual
(reverting the pie-chart fix) correctly flags gen-ui-tool-based and
declarative-gen-ui.
Also fixes a separate runtime bug in the langgraph-python package
Dockerfile: WORKDIR /app left /app owned by root; the app user could
not create the .langgraph_api cache dir LangGraph's in-memory runtime
needs, so the agent crashed on boot. Added a non-recursive chown
app:app /app (preserves the original perf intent of the explicit
--chown on COPY, which avoided a recursive chown).
Follow-up to #3971. aimock supports fixture schema validation at startup via
--validate-on-load, but it's opt-in. The showcase Dockerfile did not pass
the flag, so fixtures with unrecognized response keys (e.g. "text" instead
of "content") loaded silently and only failed at request time with HTTP 500.
That's what crashed crewai-crews on startup.
Changes:
- showcase/aimock/Dockerfile: pass --validate-on-load so broken fixtures
fail the container boot, not individual requests.
- showcase/scripts/__tests__/aimock-fixtures.test.ts: new vitest spec that
loads feature-parity.json and smoke.json via @copilotkit/aimock's
loadFixtureFile + validateFixtures and asserts zero errors. Runs as part
of the existing showcase-validate CI workflow.
- showcase/scripts/package.json: add @copilotkit/aimock dependency for the
validator import.
Verified red-green: with the pre-#3971 broken "text" fixtures, validateFixtures
flags 5 errors; post-#3971 it returns zero. Docker red-green: container with
an intentionally broken fixture fails to start with "Validation failed: 1
error(s)" and non-zero exit.
The showcase aimock feature-parity fixture had five entries that used the
unrecognized field "text" instead of "content" in the response body.
aimock's /v1/chat/completions handler validates the response shape through
discriminators (isTextResponse, isToolCallResponse, etc.) and when none
match, returns 500 "Fixture response did not match any known type".
When CrewAI's ChatWithCrewFlow.__init__ calls generate_input_description_with_ai,
it sends a prompt containing "Reporting Analyst" / "reports" text (from the
LatestAiDevelopment crew definition). aimock substring-matches this against
the "report" fixture, which had the broken "text" shape, and returned 500.
CrewAI treats that as an InternalServerError, the crewai-crews container
crashes during module import (before uvicorn binds), Railway healthchecks
fail, and the deployment rolls back to the previous ACTIVE build.
Fix:
- Convert the 5 fixtures with "text" (plan, steps, mars, dashboard, report)
to the valid "content" field so they return 200 OK.
- Add a targeted fixture that matches CrewAI's exact startup prompt prefix
("Based on the following context, write a concise") and returns a clean
text description. This catches generate_input_description_with_ai and
generate_crew_description_with_ai before they can fall through to the
more generic fixtures, providing a more predictable response for CrewAI
startup.
Verified locally against @copilotkit/aimock@1.10.0:
- Before: the CrewAI-style prompt returns 500 with the exact error message
seen in Railway logs.
- After: returns 200 with a valid chat.completion envelope.
Note: CrewAI's blocking LLM call at module import remains fragile (any
aimock hiccup crashes the container before it can bind a port). That is
an upstream issue and will be tracked separately.
Jordan Ritter