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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the safety profile is handled. The description adds real value beyond that by disclosing that the analysis is 'heuristic' (i.e. approximate, possible false positives) and provider-agnostic ('Any provider'), which an agent needs in order to weigh findings.

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?

Front-loaded with purpose, then a compact list of detection categories; the trailing 'Any provider; heuristic.' fragments are terse but each carries real meaning. No sentence is filler, though the fragment style is slightly clipped.

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 one-parameter, read-only analysis tool with a declared output schema and clear annotations, the description covers input format, scope (any provider) and reliability caveat (heuristic). Minor gap: it doesn't hint at how findings are graded or what the agent should do with them.

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 0% and the single 'plan' parameter is defined as an untyped object with additionalProperties {}, so the schema alone gives no guidance on expected shape. The description compensates by naming the exact required format ('terraform show -json'), which is the one piece of parameter semantics that matters here.

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 ('Review a Terraform or OpenTofu plan') and then enumerates exactly what it looks for: stateful deletions/replacements, public exposure, disabled encryption, literal credentials, broad policies, unpinned providers. This makes it trivially distinguishable from cloudformation_review and iam_policy_review siblings.

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 implies the trigger ('a plan exported as JSON (terraform show -json)') and even names the exact export command, which is genuinely useful context. However, it never states when not to use it or points at alternatives (e.g. well_architected_review, iam_policy_review), so routing against siblings is left to inference.

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