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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds important behavioral context beyond annotations: results are country-dependent, include counts, and an invalid guessed origin produces a misleading empty result.

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 sentences, front-loaded with the purpose and followed by the exact usage condition. The country-specific examples are directly relevant and earn their place.

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 one-parameter discovery tool with rich annotations and an output schema, this is complete. It covers purpose, when to call it, sibling relationship, and the key empty-result pitfall; return-format details are appropriately left to the output schema.

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 sole country_code parameter is already documented as comma-separated. The description reinforces country-scoped behavior and gives country-specific vocabulary examples, but does not add syntax or default behavior beyond the schema.

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 first sentence names the exact resource (origin values), scope (per country), and payload (transcript counts). It also distinguishes this discovery tool from list_transcripts by explicitly saying it is used to discover valid origin filters.

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 explicitly tells the agent to call this before list_transcripts to discover valid origin filters. It also explains why guessing fails: country-specific vocabulary means a bad value returns an empty list that looks like no sessions.

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