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

Adds context the annotations cannot express: token consumption ('Consumes extraction and recommendation tokens'), a no-write guarantee ('without inserting entries'), and a caller-ownership/auth scoping constraint ('caller-owned'). These reconcile why readOnlyHint=false but destructiveHint=false, which would otherwise be puzzling.

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 short sentences, each carrying distinct load: what is parsed, the ledger credential rule, and the side-effect/cost profile. Nothing is padded and the core action is front-loaded.

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?

An output schema exists, so return values need no explanation; what remains — required permission, cost, and absence of writes — is all covered. For a 2-parameter read-adjacent tool this leaves no material gap.

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 already 100%, so baseline is 3; the description nonetheless adds the accepted file types ('image/PDF') and the credential-dependent requiredness of ledger, which the schema states tersely. It stops short of explaining objectKey format details or failure behavior for expired temp objects.

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 and resource ('Parse the caller-owned temporary image/PDF named by objectKey') plus the outcome ('recommend accounts'). The clause 'without inserting entries' separates it from the mutation sibling insertReceiptTransaction, and 'receipt' separates it from the generic parseFile.

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?

Gives conditional selection guidance for the ledger parameter: 'Pinned credentials may omit ledger; others must select it.' It also clarifies the boundary against entry-creating tools via 'without inserting entries', though it never names insertReceiptTransaction as the follow-up alternative explicitly.

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