Tool schemas contain duplicate `required` entries, violating JSON Schema 2020-12

[jb-chief]

Some tool schemas returned by the Composio API have duplicate entries in their required arrays. This violates JSON Schema 2020-12 §6.5.3 which states:

The value of this keyword MUST be an array. Elements of this array, if any, MUST be strings, and MUST be unique.

This causes Anthropic's Claude API to reject the entire tool request with:

tools.N.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12

Because Anthropic validates all tool schemas upfront and rejects the batch if any single schema is invalid, this breaks inference for all users who have the affected toolkits connected — not just calls to the offending tools.

Affected tools (as of current snapshots)

Tool	Duplicate entry in required
GITHUB_UPDATE_A_REPOSITORY_VARIABLE	items 0 and 2 are identical
INTERCOM_ATTACH_A_CONTACT_TO_A_COMPANY	items 0 and 1 are identical

Reproduction

import Ajv2020 from "ajv/dist/2020";
const ajv = new Ajv2020({ strict: true, allErrors: true });

const schema = /* fetch tool schema from Composio API */;
ajv.validateSchema(schema.inputParameters);
// => false, "required must NOT have duplicate items"

Workaround

We deduplicate required arrays client-side at load time.

Suggestion

This is the second schema conformance issue we've hit (the first was #2330 — property keys exceeding 64 chars / containing $ characters). Both cause the same symptom: Anthropic rejects the schema → NoOutputGeneratedError. It might be worth adding ajv 2020-12 validation to your schema generation pipeline to catch these before they ship.

[Uday-sidagana]

Hey @jb-chief, I just checked the tool schemas for the above tools and there are no duplicates in required. Could you confirm the same and share a reproducible code snippet? This will help us debug the issue.

[haxzie]

Seems like an API issue, we have relayed this to our team and will be fixed soon 🙌🏽

[Uday-sidagana]

@jb-chief, adding few details to unblock the issue. It seems to be related to the older version of the toolkit . By default, we pin the 00000000_00 version, and the schema of the toolkit’s older version is causing the error. Could you try using the latest version of the toolkit? Lmk if you need help with the same.