Get invoice attachment

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description only needs to add context. Describing the operation as 'fetches' is consistent with those annotations and adds the minor signal that this returns metadata rather than file content, but it adds no substantive behavioral context beyond that. No contradiction with annotations.

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 words of front-loaded substance with zero waste — the purpose is understandable in under a second. Slightly more verbose than needed for a get-by-ID metadata fetch, and appropriate to the trivial complexity of the tool, though it borders on under-specified rather than efficient.

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 2-param, no-output-schema tool with comprehensive annotations covering safety, the description covers the essentials: it fetches attachment metadata. What's missing is an explicit note that this is distinct from downloading the binary content (the download sibling), but given the tool's simplicity, the gap is small.

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%, so the schema documents both parameters. The description's mention of 'metadata' loosely implies attachmentId identifies the attachment and that the return is not a binary download, but it adds no actual meaning about what invoiceId/attachmentId are or what format they take. Baseline 3 according to the high-coverage rule.

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?

Uses a specific verb+object combo ('Fetches attachment metadata') that identifies both the resource and its scope. The word 'metadata' differentiates it from the near-named sibling bokio_download_invoice_attachment, though it doesn't explicitly name that sibling or state it returns a single record by ID.

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?

No guidance on when to use this tool versus alternatives. In a list of ~40 siblings including the confusingly similar bokio_download_invoice_attachment and bokio_get_invoice, there's no when-to-use statement, no exclusions, and no mention of alternatives — the agent must infer intent entirely from the name.

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