CPA: call by callId

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

Description adds value beyond annotations by stating 'spends no money' and 'includes a link to the recording'. Annotations already declare readOnlyHint=true, which is consistent. No contradictions.

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?

Three sentences, each serving a distinct purpose: action, behavior, usage context. No redundancy, front-loaded with main action.

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?

Low complexity tool with single parameter and good annotations. Description covers purpose, behavior, and source of input. No output schema exists, but 'full CPA call model' plus recording link is sufficient.

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 for callId already provides full context: 'CPA call identifier (callId, int64), obtained from cpa_get_calls_by_time_v2'. Description adds no further parameter information, and schema coverage is 100%, 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?

Description clearly states 'Returns the full CPA call model by callId' with specific verb and resource. It distinguishes from siblings by mentioning it's v2, a replacement for deprecated v1, and notes usage context with cpa_get_calls_by_time_v2.

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 says 'Use when the callId is already known (from cpa_get_calls_by_time_v2)', providing clear when-to-use and referencing a sibling tool for the input. Also states read-only and spends no money, guiding appropriate usage.

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