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

With no annotations, the description carries full transparency burden. It discloses the mechanism (calls SimulatePrincipalPolicy), the return format (resolution and evaluation fields), and the credential requirement (without them, evaluation=unknown with reason). This is a substantial disclosure of behavior, though it does not state whether the operation has side effects or mention rate limits.

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 three sentences, front-loaded with the primary purpose, then mechanism, then requirements/edge case. Every sentence adds value, and there is no fluff or repetition. This is exemplary conciseness.

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?

Given the tool has no output schema and no annotations, the description covers purpose, mechanism, return values (resolution and evaluation), and the credential failure mode. It is reasonably complete for a pre-flight check, though it could elaborate on edge cases like 'unresolved' or error conditions. Overall, it provides enough context for an agent to select and invoke the tool.

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 detailed descriptions for workflow, operations, and principal_arn. The description adds contextual meaning by explaining that the tool resolves IAM actions and simulates against the current role or given principal, but this largely mirrors schema info. Baseline 3 is appropriate as the schema already provides strong parameter semantics.

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 clearly states it is a 'Pre-flight authorization check for an AWS operation', with specifics about resolving IAM actions and using SimulatePrincipalPolicy. It distinguishes itself from siblings like list_workflows and verify by its focus on policy simulation and authorization evaluation.

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 provides clear when-to-use context: before an AWS operation to check authorization. It also notes a requirement (AWS credentials) and its failure mode, but does not explicitly mention alternatives or exclusions. This is clear context without explicit alternatives, matching the 'clear context, no exclusions' level.

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