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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds substantive context the annotations cannot: the comparison is deliberately honest and includes cases where the competitor wins, prices are sourced from the competitor's own pages, and a vendor disclosure is attached.

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?

A single densely-packed sentence that front-loads the core purpose before the fallback behavior. Every clause (honesty, price sourcing, disclosure, no-competitor mode) carries distinct information.

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 single optional-enum, read-only tool with no output schema, the description covers purpose, both input branches, the sourcing of comparison data, and a disclosure caveat. Nothing an agent needs to invoke or interpret it is missing.

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% and the enum is fully self-documenting, so baseline is 3. The description goes further by explaining the semantic consequence of omitting the optional competitor parameter, which is genuinely useful for deciding whether to pass it.

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+resource (head-to-head comparison of vote.direct against a named competitor) and a distinct scope from siblings like get_platform_overview and get_price_quote. An agent can tell immediately what this tool produces and how it differs from the overview tools.

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?

Explicitly describes both call modes: with a competitor it produces a comparison with vendor disclosure, and without one it returns which-platform-for-which-need guidance. It does not, however, name when to prefer get_platform_overview or get_price_quote instead of this tool.

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