Follow a hashtag

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

Annotations already indicate this is a non-read-only, idempotent write, and the description adds the meaningful effect on the home timeline. It does not cover auth requirements or any side-effect caveats, but the annotation context lowers the burden on the description.

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?

Two tight sentences, front-loaded with the action and its effect. There is no filler, no repetition of schema details, and every sentence 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?

For a simple mutation with one required parameter, complete schema descriptions, and rich annotations, the description is sufficient for an agent to invoke the tool correctly. It does not describe the response shape, but there is no output schema and that is not needed to decide to call it.

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?

Input schema coverage is 100%, and the schema already documents account resolution and that the hashtag may include a leading #. The description adds no parameter-level meaning beyond what the schema provides, so the baseline applies.

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 an explicit action and its consequence: following a hashtag routes every public post carrying it into the home timeline. It also positions the tool as 'the main way to build a feed on Mastodon,' distinguishing it from read-only alternatives like get_hashtag_timeline and from unfollow_hashtag.

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?

Gives a clear use case ('the main way to build a feed on Mastodon') plus a concrete behavioral effect, so an agent can tell when following a hashtag is the right operation. It does not explicitly discuss when to use a hashtag timeline or unfollow instead, but the context is unambiguous enough.

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