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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description adds real behavioral value beyond them: it documents what a failed post returns (error_message, retry_count), that the reason connection_lost requires reconnecting the account before anything else publishes, and it routes to chirpie_list_accounts for identifying the account. It stops short of describing the success-path payload shape.

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 core action is front-loaded in the first sentence, and the following clauses are dense with operational detail rather than filler. The last two clauses run long and pack several ideas (error fields, connection_lost, list_accounts) into one sentence, but each idea earns its place.

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?

There is no output schema, so the description carries the burden of explaining returns, and it does cover the important failure-state fields and the platform_post_url link for a single-post fetch. Missing coverage of the general success payload keeps it from being fully complete for a lookup 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?

With one parameter at 100% schema description coverage, the schema already documents id as the post ID. The description restates 'by ID' without adding format, sourcing, or ambiguity guidance, so it contributes no meaning beyond the schema. Baseline 3 is appropriate.

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: 'Get a single post by ID.' It is clearly distinguishable from bulk siblings like chirpie_list_posts and mutation siblings like chirpie_update_post. It does not, however, explicitly name a sibling to differentiate itself.

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 implied (fetch one post's details, especially when diagnosing a failed publish) rather than stated. The description notes that a Threads/Instagram post without a platform_post_url will have it 'asked for again here', which hints at a lookup use case, but it never contrasts this with chirpie_list_posts or other retrieval paths.

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