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

Annotations provide readOnlyHint=true, but the description adds valuable behavioral context: it reads from a synced graph (potentially stale), mentions total_followed as the synced total, and explains the no-account-connected scenario (returning a link). These go beyond the annotation and help the agent understand real-world behavior.

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 three sentences, front-loaded with the core purpose, then covers query usage and behavioral caveats. Every sentence adds value with no redundancy or filler. It is appropriately concise for the tool's complexity.

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 there is no output schema, the description covers return fields (name, @handle, bio), the synced nature, total_followed, and the connection-failure link. It does not explicitly describe pagination or limit behavior, but those are documented in the schema. Overall, it is sufficiently complete for an agent to call this tool correctly.

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 already describes all three parameters with 100% coverage. The description adds a clarifying example for query ('who do I follow in AI?') and reinforces the handle parameter's purpose, but does not significantly extend the schema's meaning. With high schema coverage, a 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?

The description clearly states the tool returns 'Accounts the user follows on X (Twitter)' with fields name, @handle, and bio. It distinguishes itself by mentioning 'from the synced follow graph', which separates it from siblings like get_twitter_profile, but does not explicitly name alternatives. The purpose is specific and unambiguous.

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?

The description gives a concrete usage example for the query parameter and notes a key limitation (reads last sync, so a just-followed account may be missing). However, it does not mention alternatives or when not to use this tool versus related tools like get_twitter_profile or search_tweets, leaving some routing to inference.

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