whoami

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

No annotations are provided, so the description carries the burden. The verb 'Show' implies a read-only operation with no side effects, which is a positive signal. However, it does not disclose any output format or potential edge cases (e.g., what happens if session context is missing). Given the simplicity, a 3 is appropriate—the description adds some context (effective project scope) but could be more explicit about behavior.

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?

Two short sentences with zero filler. The primary action and scope are front-loaded, and the usage instruction is compact. Every word contributes to the tool's understanding.

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 zero-parameter, read-only introspection tool, the description covers the essential information: what it shows and when to call it. It does not describe the return format, but since there is no output schema, that is not required. It is complete enough for an agent to invoke it correctly in a new session.

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?

There are zero parameters, so the baseline is 4 as per the rubric. The description does not need to elaborate on parameters, and the empty schema fully documents their absence.

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 a specific verb ('Show') and a precise resource ('this session's actor identity and effective project scope'). It clearly distinguishes this tool from siblings like project_list or todo_list by focusing on session-level introspection, so an agent can tell its purpose without ambiguity.

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 instructs to 'Call this first in a new session,' giving a clear when-to-use condition. It does not mention alternatives or when-not-to-use, but since it is a session setup call, the guidance is sufficient for basic usage.

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