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

Annotations already declare readOnlyHint and openWorldHint, but the description adds substantial behavioral detail: the return structure (component/field/pricing changes), default comparison semantics, the fact that pending drafts are not used, and the `session_id` credential requirement. These go well beyond the annotations and clarify tricky state-dependent behavior.

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 description is compact and organized: a top-line summary, a defaults paragraph, an explicit-version sentence, and a requirement line. The reference to '#1392' is minor noise but does not detract significantly. Overall, it is appropriately sized with no wasted sentences.

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 no output schema, the description compensates by explaining what the tool returns (component-level changes, field-level details, pricing deltas). It also covers default behavior, state-dependent baselines, and required credentials, making it sufficiently complete for an agent to invoke correctly.

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 each parameter already well-documented (defaults, types, patterns). The description reinforces the defaults for from_version/to_version but adds no new semantic detail beyond the schema. This meets the baseline of 3 for high schema coverage.

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 description states a specific verb+resource: 'Structured diff showing what would be deployed if the user ran tfdeploy now.' It clearly distinguishes from siblings like stackversions (listing versions) and tfplan (planning a run), making the tool's purpose unambiguous.

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: to preview deployment impact, with defaults comparing last deployed version to current live design. It also explains edge cases (empty baseline before deployment or after destroy) and prerequisites (session_id). However, it does not explicitly name alternative tools or state when not to use it, so it falls 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.