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

Annotations already declare idempotentHint=true and destructiveHint=false, so the description earns credit for going beyond them: it discloses the post is private, explains the dual auth path (Bearer header or key argument), and warns that the key may be retained in client history and must not be shared. It still omits failure behavior (missing permissions, nonexistent community) and any rate limits.

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 purpose then retry guidance then auth. The key-handling warning is largely duplicated verbatim from the key parameter's schema description, which is a small amount of wasted space but the text remains tight overall.

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 a write tool with no output schema, the description covers privacy semantics, idempotency, and authentication, and annotations cover the safety profile. It is missing error/permission outcomes and return shape, but nothing essential to invoking it correctly is absent.

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 50%. The description restates the request_id idempotency contract and expands on the key parameter's security handling, but these are already documented in the schema. The undocumented parameters (community_id, title, body, kind) get no added meaning from the description, so it only partially compensates.

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?

States a specific verb and resource ('Create a private post in a community') plus a scoping constraint ('this account can write to'), which already distinguishes it from reply-oriented siblings like community_reply. It does not explicitly name or contrast with the close sibling create_thread, so it falls short of a 5.

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?

The description gives useful retry guidance ('Use a stable request_id for safe retries') but never states when to choose this tool over create_thread, community_reply, or community_post_moderate. Usage context is implied by the word 'post' rather than spelled out.

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