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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=true), so the bar is lower. The description adds the useful 'one vote per key' constraint that explains the idempotency, but says nothing about what a vote changes visibly, whether it can be withdrawn, or what the response contains.

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, front-loaded with the action and the key constraint, with the example kept minimal. The example slightly duplicates what the schema already declares, which is the only wasted space.

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 mutating, open-world vote tool with no output schema, an agent still lacks the effect of the call (does it return a new vote count?) and whether voting is reversible. The core action and idempotency rule are covered, so it is adequate but with recognizable gaps.

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 both parameters (key, suggestion_id) are already fully documented in the schema. The example payload mostly restates the schema and only marginally reinforces the fbk_ prefix format, so 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?

States a specific verb and resource: vote/endorse a suggestion on the public board. It distinguishes from the read-side sibling (read_suggestion_board) and the creation-side sibling (suggest_faceabot_improvement) by implication, though it never names them.

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 says what happens but never when to call this versus read_suggestion_board (to browse) or suggest_faceabot_improvement (to post). The only constraint given, one vote per key, is a rule rather than usage guidance, and no prerequisites or exclusions are stated.

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