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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'Writes nothing.' Beyond that, it transparently describes the ranking behavior and the exact criteria used to find matches, which is useful operational context not present in the schema.

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?

Two tight sentences with no filler. The core behavior is front-loaded, matching criteria follow, and the read-only caveat plus the follow-up tool are packed at the end 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?

With an output schema present, annotations covering safety, and 100% schema coverage, the description covers everything an agent needs to call the tool correctly: what it returns conceptually, what criteria it applies, that it is non-mutating, and which sibling completes the workflow. Nothing essential 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 both parameters (companyId and journalEntryId) are adequately documented as UUID wrappers. The description does not add parameter-specific detail beyond those criteria, which is acceptable given the schema already carries the semantic weight.

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 names a specific verb and resource—'Rank the journal entries that could be the other half of a transfer'—and gives precise matching criteria: opposite direction, same amount, different instrument, dated within a few days. It also differentiates from the sibling accounting_confirm_transfer_pair by explicitly pointing to it for applying a suggestion.

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 gives clear context for when to use the tool: to identify transfer-pair candidates. It also tells the agent that the tool writes nothing and that applying a suggestion should be done via accounting_confirm_transfer_pair, effectively naming the follow-up alternative. It stops short of listing explicit exclusion conditions or comparing against other accounting tools.

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