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

Annotations already declare destructiveHint=true and idempotentHint=false; the description adds genuinely new behavioral context by requiring user approval and forbidding blind retries after ambiguous outcomes. It stops short of saying what an attempt returns or what happens if no matching reaction exists, but it is well above the annotation baseline.

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 short sentences: purpose first, then the safety/retry rules. No filler, no restating of the name, and the most operationally critical warning is placed where a reader will hit it.

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 destructive, non-idempotent mutation with no output schema, the description covers the important risk surface: approval requirement and uncertain-failure handling. The remaining gap is the post-mutation outcome (what happens when no reaction is present, what a success result looks like).

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 description coverage is 75% and the params themselves document post_id format, allowed reaction values, and react_as identity rules. The description only gestures at react_as via 'this identity's' and adds no format or constraint detail beyond the schema, so baseline 3 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?

The verb+resource pair ('Remove ... selected reaction') is specific enough to act on, and the title names the Facebook post reaction context. However, the description body never says 'post' — 'this identity's selected reaction' would equally describe facebook_remove_comment_reaction, so the sibling differentiation lives only in the name/title.

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?

It supplies a precondition ('preserve explicit user approval') and an explicit when-not ('Never retry after an uncertain failure') plus a corrective action ('inspect current state first'). It doesn't name the concrete inspection tools (e.g., facebook_list_my_reactions or facebook_get_post) as alternatives, but the operative guidance is clear.

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