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

Annotations only indicate readOnlyHint=false and destructiveHint=false, leaving the behavioral burden on the description. The description does disclose that it returns the new rate and the count of changed entries when re-rating is requested, but it does not mention the default behavior (future-only vs. apply_to_existing) or the side effects of the only_missing flag; these are left to the schema.

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, both information-dense and front-loaded with the core action. No wasted words or redundant restatements of 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?

Given the rich schema and the description's explicit mention of return values, the tool is adequately described for an agent to call it correctly. Minor gaps like default behavior are covered by the schema, and no output schema exists so the return value note is sufficient.

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 already documents all five parameters. The description adds no significant meaning beyond naming 'hourly rate' and 'currency', so the baseline 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 ('Set the hourly rate and currency used to turn tracked hours into money for a project or client'). This clearly differentiates the tool from sibling entry-management and reporting tools without needing to open the schema.

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?

Provides clear context for when to use the tool (setting rates for projects/clients) and no exclusion is needed since no sibling tool competes for the same action. However, it does not explicitly state when not to use it or point to alternatives, but the context is unambiguous.

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