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

With no annotations provided, the description carries the full burden and does so thoroughly: it declares 'Read-only. No side effects. Rate-limited per your tier.' It also discloses the provider-driven nature of projection support, which warns agents that partial data is intentional rather than an error. The returned object shape is fully spelled out, leaving little behavioral ambiguity.

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?

The description is dense but every sentence earns its place: it fronts the primary result, gives concrete examples, explains why the data matters, states provider-driven behavior, and closes with explicit routing guidance. The return shape is long but directly useful since no output schema exists.

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 one-parameter read-only lookup with no output schema and no annotations, the description is complete. It covers the return structure, use cases, non-use cases, rate limiting, and data semantics. The only minor gap is not defining 'Flash projection', but the description already gives enough context that an agent can use the field correctly.

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%: the single optional 'sport' parameter is documented in the schema with examples and default behavior ('Omit for the current in-season sport'). The tool description adds no parameter-specific semantics, but the schema already covers it well. 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 ('Return') and resource ('machine-readable stat vocabulary for a sport'), then enumerates exactly what the vocabulary contains: label, family, scope, unit, display order, and projection support. It also distinguishes itself from list_sports by clarifying that this tool resolves raw stat keys into labeled, scoped markets. An agent can tell it apart from all sibling tools without opening their schemas.

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 gives explicit when-to-use guidance: after scan_props or get_game_props, to explain or group raw stat keys. It also gives an explicit when-not-to-use rule, pointing to list_sports for checking a sport's existence/access. No inference is required.

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