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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, and the description builds on that with valuable behavioral context: the target-dependent mode switch, institutional provenance, honest-empty trait vectors rather than fabricated values, and social_legibility availability. The phrase 'Requires authentication' followed by 'Institutional mode is free for all callers' is slightly ambiguous, keeping this from a 5.

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 dense but not bloated; every sentence contributes purpose, usage context, target behavior, or authentication guidance. It is front-loaded with the primary use case and then layers details, though the final authentication sentence is slightly convoluted.

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 no output schema, the description adequately explains the return concept: canonical handle, a field summary, and the institutional projection fields (provenance, trait vector, social_legibility). It also covers authentication and fallback behavior. The only gap is the exact shape of the 'summary of what the field holds for you.'

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 100% for the single optional parameter, so the baseline is 3. The description adds meaning beyond the schema by explaining the behavioral consequence of passing target, noting that today only ~alter is recognized, and that any other value falls through to the self-projection path with an added scope requirement.

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 uses a specific verb ('Find out') and a clear resource ('who the credential you are holding says you are'), then sharpens it to returning your canonical handle and session attribution. This clearly distinguishes the tool from siblings like alter_resolve_handle or alter_verify, since it is explicitly about the caller's own identity context.

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 gives concrete when-to-use guidance: 'at the start of a session, or after switching keys' to confirm attribution before acting. It also notes the authentication prerequisite and that institutional mode is free, but it does not explicitly state when not to use this tool versus a sibling or name alternative tools.

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