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composiohq__composio/plans
Alberto Schiabel b69cef123f fix(mastra): tolerate dangling $ref in tool schemas [PLEN-2451] (#3400)
## Summary

Closes
[PLEN-2451](https://linear.app/composio/issue/PLEN-2451/mastraprovider-dollardefsdollarref-schema-is-dangling-at-the-api).
Fixes https://github.com/ComposioHQ/composio/issues/3307.

The Composio API ships some tools (e.g. `GMAIL_FETCH_EMAILS`) with
`outputParameters` like:

```jsonc
{
  "type": "object",
  "properties": {
    "data": { "$ref": "#/$defs/FetchEmailsResponse" },  // ← points into $defs
    "error": { "type": "string" },
    "successful": { "type": "boolean" }
  },
  "required": ["data", "successful"]
  // ← no `$defs` block anywhere
}
```

Since [PLEN-2244](https://linear.app/composio/issue/PLEN-2244)
introduced strict `dereferenceJsonSchema`, this caused
`composio.tools.get(...)` to throw `JsonSchemaRefResolutionError: Cannot
resolve $ref #/$defs/FetchEmailsResponse` upfront via
`MastraProvider.wrapTool`, making every Gmail / Slack / Google Calendar
tool unusable through the Mastra integration.

### Approach

Two-tier fix that keeps the architectural boundary from PLEN-2244 (only
the provider that owns the validation contract pre-processes the
schema):

1. **`@composio/core`** — add an additive opt-in to
`dereferenceJsonSchema`:
   ```ts
   dereferenceJsonSchema(schema, {
onUnresolved: 'sentinel', // default 'throw' unchanged
     onReplace: (ref, reason) => { /* observe */ },
   })
   ```
In `'sentinel'` mode the unresolvable branch is replaced with the same
`{ type: 'object', additionalProperties: true }` cycle-break sentinel
the resolver already uses for `$ref` cycles. Safety caps
(`MAX_REF_CHAIN_DEPTH`, `MAX_NODE_DEPTH`) keep throwing in both modes.
Default behavior is byte-for-byte unchanged — first-party / custom-tool
authors who typo a `$ref` still see a hard error.

2. **`@composio/mastra`** — opt `wrapTool` into sentinel mode for both
`inputParameters` and `outputParameters` and emit one `logger.warn` per
`(toolSlug, ref)` pair via a provider-scoped dedup `Set`. The warning
names the tool / toolkit / pointer and links to
https://github.com/ComposioHQ/composio/issues/3307.

### Why not centralize the dereferencing in `Tools.ts`?

- Mastra is the only provider that wraps `outputParameters`. Vercel /
OpenAI / Anthropic / Google bind tool input schemas to function-calling
APIs that ignore output shapes.
- Centralized dereferencing would silently mutate `tools.get()`'s public
output shape for callers iterating raw schemas.
- PLEN-2244 set the precedent — the provider that owns the validation
contract pre-processes its own schemas. This PR mirrors that boundary.

### API-side follow-up

The proper long-term fix is for the Composio API to emit a top-level
`$defs` block alongside any `$ref` it produces. That belongs in a
separate backend ticket — the SDK fix is intentionally independent so we
don't block on a backend rollout. The SDK now degrades gracefully
regardless of which API version it talks to.

## Test plan

Red-green TDD — every new test was confirmed red against the pre-fix
`dereferenceJsonSchema` / `MastraProvider`, then green after the fix.

- [x] **Core** — 9 new cases in
`ts/packages/core/test/utils/jsonSchema.test.ts` under `describe("with
onUnresolved: 'sentinel' lenient mode")` covering: missing-target,
missing-key, malformed-pointer (non-`#/` ref), mixed schema (resolvable
+ dangling siblings), `onReplace` reasons, safety-cap-still-throws
(chain & node depth), explicit `'throw'` matches default, `onReplace`
not called in strict mode.
- [x] **Mastra** — new file
`ts/packages/providers/mastra/test/mastra-dangling-defs.test.ts` (6
cases, un-mocked `@mastra/schema-compat`): replicates the exact
`GMAIL_FETCH_EMAILS.outputParameters` shape; verifies no throw, no
surviving `$ref` in the produced schema, exactly one warn per `(slug,
ref)` pair across repeat wraps, a separate warn per slug, symmetric
tolerance on `inputParameters`, and a regression guard for resolvable
`$defs` (PLEN-2244 contract).
- [x] **Regression** — all 908 core tests, all 39 existing
`mastra.test.ts` cases, and all 3 `mastra-ref.test.ts` cases continue to
pass. Full TS workspace test run: 14 packages green, 1322 tests total.
- [x] `pnpm typecheck` passes in both `@composio/core` and
`@composio/mastra`.
- [x] `pnpm lint` on touched files produces no new warnings.
- [ ] **Manual** (post-merge, against live API):
`composio.tools.get(userId, { tools: ['GMAIL_FETCH_EMAILS'] })` returns
a `MastraTool` whose `outputSchema` is defined; SDK logs exactly one
warning per process per `(slug, ref)` pair.

## Files

```
ts/packages/core/src/index.ts                                      # new type exports
ts/packages/core/src/utils/jsonSchema.ts                           # opts + lenient branch
ts/packages/core/test/utils/jsonSchema.test.ts                     # 9 new cases
ts/packages/providers/mastra/src/index.ts                          # opt-in + dedup warn
ts/packages/providers/mastra/test/mastra-dangling-defs.test.ts     # 6 new cases
.changeset/fix-mastra-dangling-defs-ref.md                         # core/mastra patch
plans/fix-mastra-dangling-defs-ref.md                              # design + acceptance log
```

---------

Co-authored-by: jkomyno <12381818+jkomyno@users.noreply.github.com>
2026-06-04 23:53:13 -07:00
..