invoke_capability

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

Annotations cover the safety profile (readOnly=false, destructive=false, idempotent=true, openWorld=false), and the description adds non-obvious behavior: quota consumption, metadata logging, local key requirement, and a no-auto-retry policy. That is genuine context beyond the structured fields. It stops short of describing failure/error behavior.

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?

Roughly five short sentences, all front-loaded with the core behavior and constraint. The telegraphic final fragment ('No auto-retry, LLM or payment.') is dense but each clause 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?

There is no output schema, so the description is the only source for return information, yet it never says what a computed result looks like or how errors surface. Prerequisites, quota, logging, and retry policy are well covered, but the agent cannot anticipate the response shape.

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 0%, so the description must compensate, and it does so for attemptId (uniqueness, non-secret, reuse rule), which is meaningful beyond the regex pattern. It adds nothing about 'input' (free-form per-capability payload) and does not explain that 'tool' selects which built-in computation runs, leaving two of three parameters under-specified.

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 states a specific verb ('Compute') and resource ('a FREE built-in result'), and the schema's enum clarifies the seven computable capabilities. It does not explicitly distinguish itself from get_capability/search_capabilities, but the word 'Compute' versus their lookup semantics is reasonably evident.

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 gives real operational guidance for attemptId (unique, non-secret, reuse only for identical input after an uncertain response) and a prerequisite (limited key in local configuration). However, it never says when to prefer this tool over get_capability or search_capabilities, so sibling routing is left implicit.

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