espnfantasy_player_card

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

The description provides the exact return shape, clarifies that statSourceId 0=actual and 1=projected, includes a complete request example, and discloses authentication behavior (works without key; cookie unlocks more). This adds substantial value beyond the readOnly/idempotent annotations, which are consistent with the described behavior.

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 well-organized into a purpose statement, return type, example, and auth note. Every section serves a functional purpose, with no redundant filler. The JSON example is compact and aids comprehension. It is longer than a simple two-sentence description but is appropriately detailed for a tool with five parameters and no output schema.

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?

Given the tool has 5 parameters and no output schema, the description compensates by providing a return structure, a full example, and auth context. It explains the meaning of key fields and the filter construction. The description is complete enough for an agent to call the tool effectively without additional documentation.

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?

The schema already provides 100% description coverage for all 5 parameters. The tool description adds a concrete example that demonstrates how to construct fantasy_filter, including the 'additionalValue' logic ('00'+season actual, '10'+season projected). This enriches parameter understanding beyond the schema's static descriptions.

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 clearly defines the tool as a 'Deep card for specific players' with full season and per-period stat splits and projections. It identifies the resource (player card) and scope (specific players), which distinguishes it from list-oriented sibling tools like espnfantasy_players. Although no explicit verb is used, the noun phrase is unambiguous and specific.

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 usage for specific players (as opposed to lists) and provides an example with a single player ID. However, it does not explicitly state when to use this tool over alternatives such as espnfantasy_player_info or espnfantasy_players, nor does it state when not to use it. Usage guidance is thus implied but not explicit.

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