mirror of
https://github.com/CopilotKit/CopilotKit.git
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Mike Ryan
36d9f16a26
Closes OSS-901.
## Problem
`/mastra/generative-ui/a2ui/fixed-schema` could not be followed. A
Mastra onboarding run on Codex stopped there rather than invent an API,
reporting that the guide "depends on unbundled showcase helpers."
That is true, and the mechanism is worse than the report. Region bodies
are assembled at bundle time, so what ships is invisible in a source
diff. The `backend-render-operations` marker sits on **line 1** of
`mastra/src/mastra/tools/index.ts` — put there by the marker-hoist sweep
in 34b6418 so snippets would carry their imports — and the closing
marker is at the bottom of the file. The page therefore published **all
432 lines** of the tools barrel: weather, stock price, dice, d20,
query-data, schedule-meeting, search-flights, the aimock
header-forwarding import, and
```ts
import { generateA2uiImpl, buildA2uiOperationsFromToolCall } from "@copilotkit/showcase-shared-tools";
```
`@copilotkit/showcase-shared-tools` is not a package. It is a tsconfig
`paths` entry (`mastra/tsconfig.json:23`) pointing at `./shared-tools`,
a symlink to `showcase/shared/typescript/tools`. There is nothing for a
reader to install.
Same defect on the strands page from the same sweep: 586 lines of a
1688-line `agents/agent.py`.
## What changed
**The two cells get a dedicated module for the A2UI tool**, so hoisting
the marker to the top of the file yields exactly the tool plus its own
imports. This is the shape of the reference cell
(`langgraph-typescript/src/agent/a2ui-fixed.ts`, which likewise builds
A2UI operations locally) and, on the Python side, of `gen_ui_agent.py` /
`a2ui_dynamic.py`.
| page | before | after |
| --- | --- | --- |
| mastra fixed-schema | 432 lines, 16.5 KB | 166 lines |
| strands fixed-schema | 586 lines | 171 lines |
Every line in the new snippets either installs from npm or is a visibly
local `./` / `@/` module carrying a comment about what a real app uses
instead. Mastra keeps a single operation builder — the beautiful-chat
flight tool now calls the same one. The strands cell also highlights
`tools/generate_a2ui.py` so the guide shows the helper the tool calls.
**A guard in the bundler**, because neither failure mode shows up in
review:
- any `@copilotkit/showcase-*` specifier in a published body fails the
build (corpus is at zero after this change, so no baseline);
- over 200 lines fails the build (median region is 28, p90 is 125; the
48 already over the line are baselined by `slug::region::file` and the
list only shrinks).
**The entrypoint half of the issue lands differently than I first read
it.** OSS-901 flagged `@copilotkit/runtime` +
`@copilotkit/react-core/v2` on the shared A2UI page as a v1/v2 trap. It
is not a broken pairing — v1's `CopilotRuntime` forwards `a2ui` (and
`mcpApps` / `openGenerativeUI`) straight to the v2 runtime
(`packages/runtime/src/lib/runtime/copilot-runtime.ts:414`). But #6618
landed while this branch was open and retired the v1 runtime adapter
across every showcase integration, so the page's v1 root import *was*
the stale half. The block also imported `ExperimentalEmptyAdapter` and
`copilotRuntimeNextJSAppRouterEndpoint` and used neither, so it was a
route a reader could not run. It now shows `createCopilotRuntimeHandler`
from `@copilotkit/runtime/v2` in the single-route form, matching the
rebased showcase route and `/runtime-server-adapter`, with a note that
the legacy form still works.
**On the systemic question.** A separate sweep counted ~50 regions whose
marker sits on line 1 with a matching close at end-of-file, and proposed
failing a region that spans >=90% of its file. That rule does not
survive contact with the published bodies: of 141 regions at >=90% span,
only **2** publish more than 200 lines, and 98 publish under 100 —
dedicated single-purpose files whose whole content *is* the intended
snippet. It would also flag this PR's own fix
(`strands/a2ui_generate.py` is 171/188 = 91%) and the langgraph
reference cells. Published size is the signal that separates the defect
from the pattern, which is what the guard here measures.
## Testing
**Guard catches the pre-fix tree** (restored HEAD sources, moved the new
modules aside, ran the bundler):
```
REAL EXIT=1
Region bodies importing repo-only modules:
mastra::agentic-chat: region "weather-tool-backend" (src/mastra/tools/index.ts) imports "@copilotkit/showcase-shared-tools", ...
mastra::agentic-chat: region "backend-render-operations" (src/mastra/tools/index.ts) imports "@copilotkit/showcase-shared-tools", ...
Region bodies over the published-snippet limit:
strands::a2ui-fixed-schema: region "backend-render-operations" (src/agents/agent.py) publishes 586 lines (limit 200) ...
```
and passes on this branch (`bundler exit=0`, 801 demos bundled).
**Guard unit tests** —
`showcase/scripts/lib/__tests__/demo-region-guard.test.ts`, 10 passed.
Mutation-checked: raising `MAX_REGION_LINES` and short-circuiting the
alias scan fails exactly 2 of them; restoring passes 10/10.
**Showcase script suites** — `demo-region-guard`, `bundle-demo-content`,
`validate-parity`, `verify-shell-docs`, `validate-shared-symlinks`:
**151 passed (5 files)**.
**Mastra vitest** — `tests/vitest/a2ui-context.test.ts`, 5 passed. The
prompt builder lives in the dependency-free `a2ui-context.ts` so this
regression test still runs without the Mastra SDK installed, as it did
before. Mutation-checked: breaking the join fails 1 of 5.
**Strands pytest** — `tests/python/test_generate_a2ui_errors.py` 11
passed (was 1 failed / 10 passed after the move, because the happy-path
test patched `agents.agent.build_a2ui_operations_from_tool_call`;
retargeted at the new module). Whole runnable suite: **40 passed**
across `test_generate_a2ui_errors`, `test_hook_injection`,
`test_sales_state_from_args`, `test_tool_call_cap`. Mutation-checked:
stubbing out the builder call fails the happy-path test.
`test_cvdiag_boundaries` / `test_instrumentor_patch` need `starlette` /
`opentelemetry-instrumentation-threading`, absent from this venv —
unrelated to this change.
**Published snippet, rendered** (`demo-content.json` after bundling):
```
mastra snippet lines: 166 | file: src/mastra/tools/a2ui-generate.ts
import { createTool } from "@mastra/core/tools";
import { z } from "zod";
import { generateText, tool as aiTool } from "ai";
// In your own app this is `import { openai } from "@ai-sdk/openai"`. ...
```
**Docs verification** — `verify-shell-docs.ts` produces a byte-identical
finding set with my two MDX edits toggled on and off (empty diff), so
the edits add no new findings. `component-imports`, `essential-content`
and the rest are unchanged; the suite's pre-existing failures are
untouched.
**Lint / format** — `oxfmt` on all changed TS, `oxlint` clean on the new
and edited files.
## Follow-ups (not in this PR)
- The 48 baselined regions are the same class of defect on other pages —
`strands::supervisor-delegation-tools` publishes 795 lines,
`strands::subagent-setup` 625, `ms-agent-dotnet::weather-tool-backend`
549. Each wants the same split.
- `claude-sdk-typescript/shared-tools/` and
`langgraph-typescript/shared-tools/` are real directories where symlinks
belong — the erosion `showcase/AGENTS.md` documents. Untouched here.
- Dropping the strands commit (`14c7351`) is safe on its own; it only
requires adding
`strands::backend-render-operations::src/agents/agent.py` to the guard
baseline.
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