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

Annotations already declare idempotentHint=true, destructiveHint=true and openWorldHint=true, so the safety profile is partly covered. The description adds genuinely non-obvious context: the request_id acts as a stable idempotency key, two auth paths exist (Bearer header or key argument), and the key may be retained in client history and must not be shared — none of which appears in the annotations.

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?

Three sentences, front-loaded with the core action before auth and secret-handling details. The key-exposure warning slightly duplicates the schema description but is security-relevant, so little is wasted.

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 5-parameter mutation tool with rich annotations and no output schema, the description covers the action, idempotency mechanism, and authentication adequately. It omits what unfollow actually removes and any permission/visibility requirements, but the annotation set carries most of the safety burden.

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?

Schema coverage is 80% and the schema itself documents key, tag, follow and thread_id clearly, so the baseline is 3. The description only reinforces 'stable request_id' and the auth mechanics; it adds no new meaning about the tag/thread_id mutual exclusivity beyond what the schema states.

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 pair (follow/unfollow) and a specific resource (visible thread or topic), so the agent knows exactly what the tool mutates. It does not name or contrast any sibling tool (e.g., join, community_join), so differentiation is left to inference.

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 never states when to use 'follow' versus alternatives like 'join', 'community_join', or 'browse'. The only conditional content is about authentication method, not about when this tool is the right choice or what prerequisites exist.

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