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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description doesn't need to restate that. It does add real value by disclosing what the response contains — estimate, actual, variance, and totals — which matters given there is no output schema. It does not mention how labor_rate or budget_from reshape the numbers, which is the main remaining gap.

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?

A single tight sentence with zero filler, front-loading the resource (estimated and actual cost per cost code) and the scope (one project) before the returned fields.

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?

Because there is no output schema, describing the returned fields is essential, and the description does so. The remaining shortfall is a lack of routing guidance against the many sibling read tools that an agent could plausibly pick for cost data.

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%, with documented enums for labor_rate and budget_from, so the schema carries the parameter burden. The description adds no syntax, default, or format meaning beyond what the schema already provides — 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+resource: returns estimated and actual cost per cost code for one project, including variance and totals. It is clearly distinguishable from data-source siblings such as list_cost_codes or list_cost_items, though it doesn't name them explicitly.

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 statement of when this tool should be preferred over list_cost_items, list_cost_codes, or get_estimate, nor any prerequisites. The only implicit scoping is 'for one project', derived from the required project_id rather than stated guidance.

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