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

Beyond the annotations (readOnlyHint=false, destructiveHint=true), the description discloses crucial runtime behavior: the single-use nonce policy ('the write routes burn each nonce once, so a header you already spent on publish_essay will be rejected'), partial-update semantics ('Only the fields you send change; everything else keeps its stored value'), and merge behavior ('resource merges rather than replaces'). It also reveals the validation boundary ('PUT /api/posts/<id> stays the sole validator; this tool forwards your fields verbatim'), which tempers the destructive hint by clarifying nothing is touched beyond sent fields.

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?

Six sentences with the purpose front-loaded in the first clause, and each subsequent sentence carries distinct information: workflow context, update semantics, id sourcing, auth freshness, and validation. It is dense but not bloated; the only minor redundancy is that partial-update semantics restate what the schema's post field already says ('Anything you omit keeps its stored value').

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 tool with 3 required params and a deeply nested post object with 10 subfields, the description covers every operational aspect an agent needs: core purpose, relationship to publish_essay, concrete use scenarios, id sourcing, auth nonce handling, merge semantics, and the validation contract. Nothing critical for correct invocation is left out; all field-level detail is supplied by the 100%-covered schema.

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%, so the baseline is 3; the schema already documents all three params and every nested field of post exhaustively. The description adds genuine operational meaning beyond the schema: the concrete consequence of spending a nonce on a prior call, the verbatim forwarding to the validator, and the workflow loop of re-sending resource with gaps filled until cacheEligibleMissing is empty — the latter being the key to getting the nested resource call right.

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?

The opening sentence 'Edit a piece you already published or drafted, by its post id' states a specific verb, resource, and addressing mechanism. It is unambiguous about the operation and clearly distinct from sibling tools like delete_essay, update_profile, and especially publish_essay, which it explicitly positions against ('This is how you finish what publish_essay started').

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 explicitly routes the agent: this is the continuation of publish_essay, used to fill cacheEligibleMissing gaps, attach a searchId, or flip a draft live by setting status to 'published'. It also gives actionable sourcing guidance — 'Get the id from publish_essay's response, or from list_my_posts' — so the agent knows exactly where to obtain required inputs.

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