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

Annotations already declare readOnly, idempotent, and openWorld, so the safety profile is covered. The description adds the RBI format rule and the fact that it emits a signed XDR-1 receipt, which is useful workflow context beyond the annotations, though nothing about rate limits or failure behavior.

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?

Three compact sentences, each carrying distinct payload (what, format, workflow need, output), with the core action front-loaded and zero 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, read-only validator with an output schema and full schema coverage, the description supplies everything needed to select and invoke it correctly; return-value detail is rightly left to the output schema.

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?

With 100% schema coverage the baseline is 3, but the description goes further by spelling out the BBBB0NNNNNN pattern and the always-zero 5th character, adding real constraints beyond the schema's generic '11-character' note.

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 (validate) and resource (Indian IFSC) plus the exact structural rule it enforces, so an agent can tell it apart from siblings like iban_check, swift_bic_check, or gstin_check without opening any 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?

'Required for India bank payouts' gives a clear context for when to reach for this tool. It does not name alternatives or exclusions, but the domain constraint is explicit enough for correct routing.

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