Validate records against a scheme

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

Annotations already indicate the tool is read-only, idempotent, and non-destructive. The description adds behavioral context by detailing the specific rules checked (charge bearer, UETR, remittance length, cardinality) and the return format including 'is_valid', 'total', and 'violations'. This adds value beyond the annotations.

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 concise and well-structured, with a clear introductory sentence, usage guidance, a bullet-like list of rule types, and an Args section. Every sentence adds value without redundancy.

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's complexity (2 params, high schema coverage, no output schema, good annotations), the description is nearly complete: it covers purpose, usage, return format, and parameter details. Minor gaps exist (e.g., error conditions, violation structure), but overall it adequately prepares the agent.

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 100%, with descriptions for both parameters. The description goes further by explaining the 'records' parameter as 'one or more flat payment records' and the 'scheme' parameter as a registered profile name from 'list_schemes'. It also lists example rule types, adding context beyond the schema enum.

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 states the verb and resource: 'Validate payment records against a scheme's usage-guideline rules.' It distinguishes from the sibling tool 'validate_records' by noting it is complementary. The purpose is specific and unambiguous.

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 explicitly says to 'Use this to check a batch against a rail's rulebook' and lists example schemes. It also mentions it is complementary to 'validate_records', providing context for when to use this tool over alternatives. However, it stops short of explicitly stating when not to use it.

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