Estimate task cost

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe read-only operation. The description's 'Does not create anything' repeats that safety profile rather than adding new behavioral context such as rate limits or account-checking side effects. With strong annotation coverage, a 3 is appropriate.

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, front-loaded sentence that states the core function, the timing ('before submitting'), and the side-effect guarantee. Every clause earns its place with zero redundancy or filler.

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 read-only estimation tool with 3 parameters (1 required) and a full output schema, the description fully covers what the tool does, when to use it, and what it does not do. Nothing an agent needs to call it correctly 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 description coverage is 100%, so the schema documents all three parameters (vip, type, url_count) with descriptions. The tool description adds no parameter-specific meaning beyond stating the task types ('indexing or index-check'), which maps to the existing type enum. Baseline 3 is correct.

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 description uses a specific verb + resource: 'Estimate the credit and USD cost of an indexing or index-check task before submitting it, and whether the account balance covers it.' This clearly distinguishes it from sibling tools like submit_urls_for_indexing and check_index_status, and the closing 'Does not create anything' reinforces the non-mutating scope.

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 phrase 'before submitting it' provides clear contextual timing for when to use this tool, and 'Does not create anything' implies it is a safe pre-flight step rather than the actual submission tool. However, it does not explicitly name alternatives like get_pricing or exclude cases where estimation is unnecessary, so it falls short of the top score.

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