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

Annotations already mark this as non-read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond that: it is an explicit user-approved save, not a background side effect, and duplicate candidates must be confirmed. This is relevant behavioral disclosure without contradicting the 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?

Two sentences pack the core action, the user-consent condition, the sibling-tool exclusion, and the duplicate policy without fluff. The most important behavioral constraint is front-loaded in the first sentence.

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 mutation tool with annotations, an output schema, and an 11-parameter schema, the description covers the critical invocation and duplicate conditions. It does not explain the optional customer fields or outcomes, but those are either self-explanatory or covered by the output schema, making it complete enough for correct selection and invocation.

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 only 18%, so the tool description needed to carry more parameter guidance, but it only meaningfully covers allowDuplicate (and references the duplicate flow). The other optional fields are left entirely to their names and schema constraints, so the description falls short of compensating for the low coverage.

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 specific verb and resource: explicitly save a reusable client. It is distinguished from create_invoice by forbidding silent calls, and the title reinforces the create-client purpose. This clearly separates it from sibling client tools like get_client, list_clients, and update_client.

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 an explicit invocation condition (after the user chose save and assign), a prohibition (never call silently from create_invoice), and a duplicate-handling policy (require confirmation before retrying with allowDuplicate=true). This tells the agent exactly when and when not to use the tool.

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