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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the write/repeat-safety profile is covered structurally. The only behavioral claim in the description (names unique per account) largely restates the 'name' schema field description, adding little beyond structured data, and it doesn't explain what happens on a duplicate (error vs upsert) or what the response returns.

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 short sentences, front-loaded with the core action and no filler. It is appropriately sized, though the second sentence's uniqueness note is redundant with the schema.

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 annotations covering the write/safety profile and an output schema present, the description needn't explain return values. However, for a creation tool it omits useful context such as the duplicate-name failure mode, whether 'color' is optional at creation, and any prerequisite permissions, leaving it only minimally adequate.

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 both the 'name' (uniqueness, max 80) and 'color' (hex format) semantics are already fully documented in the schema. The description adds no parameter detail beyond that, so the baseline of 3 is appropriate.

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 ('Add a client'), which clearly distinguishes it from read-oriented siblings like get_client and list_clients. It does not, however, differentiate itself from the other creation/mutation siblings such as create_project or create_invoice, so sibling routing is only implied.

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?

There is no guidance on when to use this tool versus create_project, update_client, or the other client-management siblings. The uniqueness note reads as a constraint rather than a usage condition, so the agent gets no explicit context or exclusions.

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