Terraform plan

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

With no annotations, the description carries the full burden and does well: it discloses immediate sandbox execution (no confirmation gate), that the plan is persisted as durable state, and that output is annotated on destructive changes like forced replacement. It omits auth/permission requirements and failure behavior, which keeps it out of 5 territory.

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?

Three tight sentences with no filler, front-loaded with what the tool does before the sandbox/persistence and destructive-change details.

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?

An output schema exists, so return values need not be explained, and the description covers execution model, persistence, and destructive-change signaling. The main residual gap is parameter semantics for working_dir, which neither schema nor description pins down.

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 0% for the single working_dir parameter, so the schema adds nothing. The description hints that the module lives 'under the terraform/ root', which weakly constrains the path, but it never states whether working_dir is absolute, relative, or relative to that root.

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 ('Computes a Terraform diff for a module'), and scopes it to the terraform/ root. It also implicitly distinguishes itself from the sibling terraform_apply by framing itself as the review step that a 'subsequent apply' consumes.

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?

Gives clear context for use: it runs immediately and produces a persisted plan that a later apply executes, which tells the agent this belongs before terraform_apply. It stops short of explicit when-not-to-use guidance or naming the alternative tool directly.

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