permission_diff

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

Without annotations, the description carries the full burden. It discloses that PSGs return an instructive error and that results are grouped by signature. However, it does not mention whether the operation is read-only, performance characteristics, or error handling for invalid inputs.

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 purpose, then providing detail and exclusion. Every sentence adds value without redundancy or unnecessary text.

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 three parameters and existence of an output schema, the description explains the return format (grouped by signature) and the PSG error behavior. However, it does not cover all potential errors or the structure of the output in detail, making it moderately complete.

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?

With 0% schema coverage, the description should compensate. It only hints that principals can be profile or permission set and does not explain the format of principal_a, principal_b, or snapshot_id. The description adds minimal parameter insight beyond the schema.

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 that the tool computes the symmetric difference of permissions between two principals (profile or permission set) and groups them by signature. It specifies it is the P1 workhorse, distinguishing it from sibling tools like find_sensitive_access.

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 explicitly excludes PSGs, stating they require P2's effective_permissions tool, providing clear when-not-to-use guidance and an alternative. It labels the tool as the P1 workhorse, implying it is the default for permission diffing in P1.

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