decode_pan_type

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

Read-only and idempotent behavior is already covered by annotations, and the description adds the specific decoding rule (uses the 4th character). This gives useful context beyond the schema without restating the annotation flags.

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 entire description is one front-loaded sentence with zero filler. Every word contributes meaning: what is decoded, from what, and where in the input.

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 single-parameter, read-only decode operation with full schema coverage and an output schema, the description is nearly complete. Minor gaps such as edge-case handling of invalid PANs or the exact entity-type mapping are not essential for correct 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?

The single parameter is fully documented in the schema as a '10-character PAN', so the description does not need to add much. It correctly implies that the 'pan' value is the input, but it adds no extra parameter-level detail beyond the schema.

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 ('Decode'), a specific resource ('PAN entity type'), and an exact source ('4th character'). This clearly distinguishes it from validation siblings like validate_pan and bulk_validate_pan without needing to inspect 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 makes the use case clear: use this tool when you need to interpret the entity type encoded in the 4th character of a PAN. It does not explicitly name alternatives or exclusions, but the decoded-vs-validated distinction is strongly implied by the phrasing.

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