Search invoices

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

Annotations already declare this read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds meaningful behavior: it wraps two underlying methods, applies a default status of 'open', and discloses what fields each result contains. This goes beyond the annotations without contradicting them.

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 sentences, numbered modes, and no filler. The critical constraint ('Provide at least one of `query` or `client_id`') and result contents are both front-loaded and expressed compactly.

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 compensates by enumerating the result fields (`id`, `id_code`, status, dates, total, paid, due). It covers the two usage modes, required-parameter constraint, and default status. The remaining parameter details are fully documented in the schema, so 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%, so the baseline is 3. The description adds value by mapping `query` and `client_id` to underlying methods, clarifying that status defaults to 'open', and explaining the free-text search scope. It does not repeat every schema detail but enhances the semantics of the key parameters.

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 opens with a specific verb and resource ('Find invoices') and immediately lays out two distinct search modes. It names exact searchable fields (invoice number, client name/email, line description) and the alternate client_id listing path, making the tool's role clear relative to single-invoice retrieval tools like get_invoice.

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 explicit selection guidance: use `query` for free-text search or `client_id` for status-filtered listing, and states 'Provide at least one of `query` or `client_id`.' It does not explicitly mention sibling alternatives or when not to use this tool, but the in-tool mode guidance is strong.

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