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

Annotations only declare write (readOnlyHint=false), openWorldHint=true, destructiveHint=false, so the description carries meaningful extra load: it discloses the consequence (new leads stop until Monday reset), that opportunities are billed separately, and the Cotlet API-key auth requirement. However, it introduces a 'switch off confirmation' option that maps to no parameter, which muddies an otherwise informative disclosure.

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?

The core statement is front-loaded, but the first two sentences are redundant and the trailing confirmation/call boilerplate ('By default you confirm each call... Reaches other people: confirm with the user before each call') reads as generic and is not clearly tied to this specific budget-setting operation.

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 single-parameter write tool with annotations and no output schema, the description supplies the behavior an agent needs (what it changes, the reset semantics, auth needs). It is only missing explicit routing to the get_budget sibling.

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 coverage is 100% and the single amount parameter is fully described there ('Whole currency units of your account'). The description adds only that the budget concerns leads, which is marginal beyond the schema, so the baseline 3 applies.

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 ('Set') and resource ('weekly lead budget'), and clarifies it means 'the most you spend on leads in a week.' The intent is unambiguous, though it never names its obvious sibling thumbtack_get_budget, leaving differentiation to inference from the verb. It also restates the same idea twice in the first two sentences.

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 explains what happens once the budget is reached (leads stop until Monday) but gives no explicit when-to-use versus alternatives such as thumbtack_get_budget, nor any prerequisites for calling it. Usage is only implied by the verb 'Set'.

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