set_card_pin

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

Discloses one behavioral trait: PIN not stored by CardOS. However, since no annotations exist, description should cover more (e.g., authentication requirements, side effects). Basic transparency but incomplete.

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, no fluff. Front-loaded with the core action and cardinality. Every word is necessary.

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?

Adequate for a simple tool with two parameters and no output schema. Covers purpose and a key behavioral detail, but lacks usage guidance and broader behavioral traits. Meets minimum viability.

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 covers 50% of params with description (card_id). pin has no description in schema but the description implies it's a 4-digit numeric string, aligning with the pattern. Adds some value but does not fully compensate for missing schema 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?

Clearly states action 'Set' and resource 'card PIN', specifies PIN length (4-digit), and adds unique detail about PIN not being stored by CardOS. Distinguishes from sibling tools which deal with other card operations.

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?

No guidance on when to use this tool versus alternatives like set_card_controls, or when not to use it. Lacks context about prerequisites or post-conditions.

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