Find likely duplicate payees

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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds context beyond them: the deliberate conservative matching policy, the fact that a false positive feeds an irreversible merge, that nothing is merged automatically, and that transfer payees are never included. This is exactly the extra behavioral context annotations cannot convey.

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?

Opens with the core grouping rule and example, then layers caveats (matching is exact, empty result meaning, no auto-merge, transfer exclusion) in order of importance. Every sentence carries distinct information; nothing is redundant.

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?

With no output schema, the description still explains the return shape (groups with suggestedTarget, candidates, and reason) and the operational caveats an agent needs before routing to merge_payees. Nothing material is missing for a one-parameter read-only analysis tool.

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% and there is a single optional parameter, so the schema fully documents minGroupSize. The description adds no further semantics about it, which is the expected baseline when the schema does the heavy lifting.

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 precise verb (group) plus resource (payees) and immediately defines the exact matching criterion with concrete examples. It clearly separates itself from list_payees and merge_payees by naming both as adjacent steps in the workflow.

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?

Explicitly says when the tool applies (name-shaped duplicates only) and when it does not ('an abbreviation and its expansion do NOT group'), warns that an empty result does not mean 'no duplicates', and directs the agent to scan list_payees and then confirm with merge_payees. Both the alternative and the exclusion condition are named.

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