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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds meaningful extra context: it discloses the returned payload (full text plus audience as distance or neighborhoods) and an auth prerequisite (Cotlet API key with access to this app). It does not mention rate limits or failure modes, keeping it short of a 5.

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?

Front-loaded ('Nextdoor: One post: ...'), three short sentences, no filler. There is mild redundancy between the field list ('title, text, audience, reactions and comment count') and the following sentence that repeats 'full text and the audience.'

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 single-parameter read tool, everything an agent needs is present: what is returned, the audience representation, the auth prerequisite, and the pointer to list_comments for the related resource. With read-only annotations and no output schema, the description compensates adequately.

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?

Only one parameter and schema coverage is 100%, with the schema stating 'Post ID from list_posts.' The description adds no syntax, format, or sourcing detail beyond that, so the baseline 3 is appropriate — the schema carries the parameter meaning entirely.

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 ('One post') and enumerates the fields returned (title, text, audience, reactions, comment count), which clearly separates it from list_posts. It stops short of explicitly naming the sibling it differs from, so an agent must infer that this is the single-item lookup versus the list tool.

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?

It routes one adjacent task correctly ('Comments are read with list_comments'), which is genuinely useful. However it never states the condition that selects this tool over nextdoor_list_posts — the agent must infer 'use when you already have a post_id' from the schema's 'Post ID from list_posts' hint.

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