Look up one bank branch by IFSC

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

Annotations already declare readOnlyHint/idempotentHint/openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the exact failure taxonomy (INVALID_INPUT, NOT_FOUND, three UPSTREAM_* variants) and the ok:true/ok:false shape. No rate limits or latency expectations, but this is strong added context.

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?

Front-loaded with purpose and usage, then well-sectioned failure codes and an example that do real work. The 'Args:' and 'Returns:' blocks largely duplicate the input schema and the output schema, which is mild waste but far from bloat.

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-lookup tool with 100% schema coverage and an output schema already present, the description covers purpose, trigger, error taxonomy and return-field inventory. Nothing an agent needs to call it correctly is missing.

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 description coverage is 100% and the single parameter is fully documented there (format, case-insensitivity, whitespace trimming, not-a-bank-code). The description restates the same 11-character rule and example, adding no meaning beyond the schema, so the baseline 3 applies.

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?

States a specific verb (retrieve) and resource (single bank branch) scoped by an identifier, and explicitly carves out uniqueness: 'the only tool that confirms a branch actually exists, and the only source of the branch's address, MICR, SWIFT/bic code...'. That contrast with ifsc_validate and the directory-style siblings is enough for an agent to route correctly without opening the schema.

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?

'Use this whenever the user supplies an IFSC' gives a clear triggering condition. It does not name ifsc_validate or search_branches as the alternative or state when NOT to use this tool, so it falls short of explicit alternative routing.

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