iam_policies

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

Annotations already carry readOnlyHint, so the bar is lower, yet the description adds real context: the risk label, the truncation-reporting behavior of the envelope, and the target defaulting semantics. These go beyond what the annotations declare.

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 the READ/risk tag, then the purpose, then concise arg notes. No filler, and the args block maps cleanly to the two parameters.

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 simple two-parameter list tool with no output schema, the description covers what is returned (policy names), truncation signaling, and target scoping. Adequate for correct invocation.

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%, so the description must compensate and largely does: it defines limit (max names to return, with truncation reported) and target (config target name, omit for default). Only minor format/syntax detail is missing.

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 what the tool returns - the canned policy names defined on the deployment - and the name/prefix 'iam_policies' plus parallel siblings (iam_users, iam_groups) make the resource distinct. It is clear but does not explicitly distinguish itself from adjacent tools such as diagnose_iam_exposure.

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 '[READ][risk=low]' tag and 'from config; omit for the default' note imply a read-only inventory call, but there is no explicit when-to-use or when-not guidance relative to the other IAM siblings.

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