cost_compare

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

With no annotations, the description carries the full burden, yet it usefully discloses that costs are estimates (not live/actual billing), that the result is a report layer, and that it covers all 'reachable' models. It omits whether the call is side-effect-free, whether it hits a live pricing API, or any rate/auth constraints.

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 tight sentences with the core action front-loaded. The parenthetical '(the monetization "report layer")' is internal jargon that does little work for an agent, a minor deduction.

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?

There is no output schema, so the description correctly sketches the return (cost report including max savings vs the most expensive reachable model). However, half its parameters are undocumented anywhere, leaving an agent guessing about region and capability filtering.

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 only 25% — only 'prompt' is documented, while region (with its global/CN enum), max_output_tokens, and required_capabilities are bare. The description only echoes 'prompt size' and adds no semantics for the three undocumented parameters, so it fails to compensate for the coverage gap.

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 ('Rank every reachable model by estimated cost') plus the output artifact (cost-comparison report with max savings). This clearly distinguishes it from the sibling list_models (enumerate only) and cache_route/route (actual routing), though it never names those alternatives.

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 implies a pre-routing comparison use case but never states when to call this versus route, cache_route, or list_models, nor any exclusions or prerequisites. No explicit 'use this when...' guidance is present.

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