whoami

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

Clearly states read-only behavior, self-scoping (never other identities), mode-dependent auth requirements, and the ungated failure/edge behavior. Explicitly explains that the resolved tool list means 'group expansion minus deny_tools'. Aligns with the readOnlyHint annotation; no contradiction.

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 identity result summary, then scope, then gating, then edge case. Dense but organized; each sentence adds a distinct fact. The parenthetical expansions ('group expansion minus any deny_tools', 'a valid per-call credential') are useful but could be trimmed slightly.

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?

Covers the reported fields, mode-based scope, permission-gating nuance, and edge case (missing manifest). Given there's no output schema, the description is largely sufficient; only the concrete response format (JSON/text) is left implicit, which is a minor gap for a diagnostic 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 gives zero description for app_id (default ''), but the description covers its meaning in both modes: OAuth-derived in serve mode, and an owned/app-bound identifier requiring valid per-call credential in local enforcement. This compensates for the 0% schema coverage.

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?

Opens with 'Report who you are and what you may do' and enumerates precisely the fields returned: app_id, role, permission groups, resolved tool list, store_scope, and human-only status. No ambiguity about what this tool does or its self-scoped nature.

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?

Describes when it's appropriate: identity/entitlement discovery, and distinguishes execution modes (serve-mode OAuth binding vs. local enforcement with credential proof). Explains the read-only, self-scoped usage and the ungated edge case for missing manifests. Lacks a concrete invocation example but the use-cases are otherwise well conveyed.

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