Pin or unpin a TikTok comment

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

Annotations already declare destructiveHint=true and openWorldHint=true, so the mutating nature is covered structurally. The description adds genuinely non-obvious context: the 'comments' capability must be present and is granted at connection time, so older connections must reconnect. It stops short of saying whether re-pinning an already-pinned comment errors or is a no-op.

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?

Action and its inverse are front-loaded in the first sentence, with the platform and capability caveats following. Slightly redundant ('TikTok only. TikTok: Requires...'), but every claim 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 4-parameter mutation tool with an output schema and full schema coverage, the description covers the action, the inverse case, platform restriction, and the auth prerequisite. Only edge-case behavior (already-pinned state, failure modes) is left unspecified, which is minor given the output schema.

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 100%, so every parameter is already documented, including pinned's default of true. The description reinforces the pin/unpin polarity and implies postId must belong to the profile's own video, but adds no format or constraint detail beyond the schema — baseline 3.

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 (pin/unpin), the exact resource (a TikTok comment), and the scope constraint (one of the profile's own videos). The 'pinned: false' clause tells an agent immediately that this tool covers both directions, distinguishing it from siblings like hide_comment, like_comment, or delete_comment.

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?

Clear about when it applies: only TikTok, only comments on the profile's own videos, and it names get_post_comments (via the schema) as the source of commentId. It does not explicitly name a sibling alternative for other platforms, but the 'TikTok only' exclusion handles most mis-selection risk.

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