Estimate change cost

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

Annotations declare readOnlyHint: false while the description asserts 'Read-only: it estimates and checks, it never applies anything' — a direct contradiction. Per the rubric, any description that contradicts annotations scores 1 and must be flagged as an Annotation Contradiction.

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?

Well-structured and front-loaded: a one-line summary, read-only callout, bulleted input options, budget behavior, good triggers, and examples. Every sentence serves a purpose, and the bullet formatting makes it scannable.

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 complex 6-parameter, multi-mode tool with no output schema, the description covers inputs, verdicts (ok/warn/over_budget/no_budget), return values (delta, headroom), defaults, and edge cases. No significant gaps exist.

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?

Despite 0% schema description coverage, the description fully compensates by explaining each input mode (Terraform plan via json/file/dir, helm_diff, and the monthly_delta_usd escape hatch) and documenting budget_name's default (first active budget) and the no_budget edge case.

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 opening line 'Cost preflight for a proposed change: what it costs and whether it fits budget' uses a specific verb+resource construction, and the description further clarifies scope ('Read-only', 'it estimates and checks, it never applies anything'), distinguishing it from siblings like get_cost_summary and check_ai_budget.

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 excellent when-to-use guidance: 'Call this BEFORE applying an infrastructure change', a 'Good triggers' list, and two example queries. However, it lacks an explicit 'when not to use' note naming alternative tools (e.g., get_cost_summary), so it falls just short of a 5.

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