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

Annotations already carry readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description then adds real behavioral context: mode semantics (spotlight limited to tier<=1, career_summary aggregates only), lane defaults, return shape (summary + events[] with named pattern labels), and the overlay call. It stops short of disclosing pagination or error behavior, so 4 rather than 5.

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?

Front-loaded with the USE condition, then exclusions, then parameters, then return shape - a sensible priority order for scanning. It is dense with pipe-separated shorthand and symbols (HR#, tier<=1), which is efficient but slightly cryptic, keeping it from a 5.

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 7-parameter tool with no output schema, the description covers the gating logic, mode/lane behavior, the required-id caveat (Retrosheet not BBRef ids), and the return payload. Only minor gaps remain (no pagination or empty-result guidance), so it is close to complete.

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 already 100%, so baseline is 3. The description adds meaning beyond the schema: mode defaults and tier coupling, lane default, limit bounds, and notably that season_yr is required for season/spotlight modes - a conditional requirement the schema does not express.

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?

States a specific verb+resource+scope: finds baseball plays where a player's season HR/K count matches calendar day, jersey number, or inning. It explicitly names what it is not (roster cardology, cosmic day card) and routes to the relevant siblings, so an agent can distinguish it from get_team_chemistry and get_date without reading 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?

Opens with an explicit USE when-condition tied to the alignment trigger, gives two NOT-for exclusions with named alternatives, and closes with an overlay instruction (get_date for MCP day-card narrative). This is textbook when/when-not/alternatives guidance.

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