Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations say destructive/openWorld, and the description adds real substance beyond them: text is optional and falls back to publishing the waiting suggestion, a distinct permission is required, and an external platform constraint governs success. The named error code and 'item stays open' outcome tell the agent exactly what a refusal looks like.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the action and audience, then the optional-parameter behavior, then the permission and refusal caveat. No sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an open-world mutation with no output schema, the description covers what the agent needs: default behavior when text is omitted, the required permission, and the exact failure mode. Nothing material is missing for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% (baseline 3), and the description genuinely adds meaning for the one non-obvious parameter: leaving text empty publishes the waiting suggestion rather than erroring. title_id and item_id semantics are left to the schema, so it's not a full 5.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource ('Reply on X to an inbox item'), scoped to 'now, on behalf of the brand'. The wording makes it distinguishable from draft_social_reply (draft vs publish now) and publish_social_post (reply vs new post) without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

States the context (reply to an inbox item), the prerequisite (requires the separate social:publish permission), and the failure path (X refuses → item stays open with SOCIAL_X_REPLY_NOT_ALLOWED). It does not explicitly name draft_social_reply as the alternative when a review step is wanted, so it falls short of a full 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.