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

The description discloses key behavioral traits beyond annotations: a cap of ~60 replies for signed-out readers, omission of replies from accounts that opted out of indexing, cross-server aggregation, and a cost of 1 credit. These are valuable operational details.

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 description is front-loaded with the core purpose and then adds relevant constraints efficiently. Every sentence contributes useful information, though the opening 'Post replies' is slightly redundant with the title.

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?

Given the annotations and lack of an output schema, the description covers the main behavioral aspects (limits, exclusions, cost) but leaves cache_max_age unexplained and does not describe the response format.

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?

The input schema has 50% description coverage (url is described, cache_max_age is not), and the description adds no meaning to either parameter. It does not compensate for the undocumented cache_max_age.

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 description states it retrieves public replies to a Mastodon post, in thread order, from every server the hosting server knows of. This is a clear verb+resource, though it does not explicitly differentiate from siblings like mastodon_post or mastodon_userPosts.

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?

No explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. The description only implies usage by stating what it returns.

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