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

Beyond the annotations (readOnlyHint, idempotentHint), the description adds that validation is performed by RBI structure—indicating a deterministic format check—and reveals the return artifact as a 'signed XDR-1 receipt.' This gives useful behavioral context that annotations alone do not provide, with no contradictions.

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 three short sentences, each adding distinct value: the validation rule, the use-case context, and the return format. It is front-loaded with the verb and pattern, with no redundant filler.

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 validation tool with full schema coverage, an output schema present, and readOnly/idempotent annotations, the description is fully adequate. It explains what the tool does, why it is used, and what it returns, leaving no critical gap for an agent to call it correctly.

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 documents the 'ifsc' parameter as an 11-character code, but the description enriches this with the exact RBI pattern (BBBB0NNNNNN) and the rule that the 5th character is always 0. This goes beyond the schema's minimal length description and clarifies the expected input format.

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 ('Validate') and resource ('Indian IFSC'), and defines the exact structural rule (BBBB0NNNNNN; 5th character always 0). This clearly distinguishes it from sibling validation tools like iban_check or swift_bic_check by pinning down the instrument type and country.

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 phrase 'Required for India bank payouts' gives a clear use case and context for when an agent should invoke this tool. It does not explicitly list alternatives or exclusions, but the India-specific framing is sufficient to guide selection among the many sibling checks.

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