market_validate

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

With no annotations, the description carries the behavioral burden. It adds useful specifics beyond a generic 'validate' wording: it notes the data is cached, optionally involves a call to /me, and gives a quota estimate ('🟢 1–2 calls'). This gives an agent a realistic sense of cost and side effects, though it doesn't explicitly state read-only behavior or error handling.

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, zero filler. The core validation purpose and data source are front-loaded, followed by the optional /me behavior and quota. Every sentence earns its 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 simple, optional-parameter validation tool, the description covers purpose, source, caching, quota, and optional behavior. There is no output schema, but the response_format parameter in the input schema already communicates the possible output styles. It could mention invalid-input handling, but nothing essential is missing for invocation.

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 already fully documents all three parameters and their semantics. The tool description adds context about ISO 3166-1 and caching but does not need to explain parameters further. 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?

The description states a specific verb ('Validate') applied to a specific resource ('ISO 3166-1 market codes') against a concrete source ('GET /markets'), and clearly distinguishes the alternate optional behavior (returning account market from /me). This is enough for an agent to understand what the tool does without opening the schema.

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 its use case—validating market codes—and even suggests an omitted-parameter behavior via the schema, but it does not explicitly state when to choose this over siblings like get_available_markets or market_availability, nor does it mention exclusivity or alternatives. The context is clear but no when-not/exclusion guidance is provided.

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