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

Annotations only declare the generic write profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false). The description adds auth scope, the fact that the first call is a no-op dry run, that it validates unknown fields and rejects them by name, and that it returns a summary plus confirm_token that must be echoed back. That is exactly the behavioral context annotations cannot supply.

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?

The action is front-loaded, then the prerequisite, then the two-step protocol, in the order an agent needs them. Four short sentences, none wasted, including the useful warning about named field rejection.

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?

With no output schema, the description does describe the first call's response (summary and confirm_token), which is the critical return value for driving the flow. It omits what the second call returns and the type/meaning of `pinned`, a minor but real gap for a mutation tool.

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 only 33%, and only confirm_token is documented in the schema; the description reinforces the confirm_token protocol well. However, `pinned` (an untyped empty schema) and `id` receive no semantic explanation — the description never says `pinned` is a boolean pin state, so it does not fully compensate for the coverage gap.

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 first sentence gives a specific verb pair and resource ('Pin or unpin a post'), which is enough to separate it from create_post/update_post/restore_post siblings. It stops short of explicitly naming those siblings or the distinction from update_post, keeping it just below 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?

Usage is spelled out with unusual precision: the required scope (`content:write`), the two-call sequence, and the human-confirmation gate before the second call. It doesn't cover when to pin versus using update_post, but the procedural guidance is clear and actionable.

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