ep_principal_lookup

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

No annotations are provided, and the description does not disclose any behavioral traits such as side effects (likely a read-only lookup), authentication requirements, rate limits, or data freshness. It only mentions return values, which is insufficient for full transparency.

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 a single sentence with no unnecessary words. It front-loads the purpose and immediately lists return values, making it efficient and scannable.

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?

The tool has only one parameter and no output schema, so the description reasonably covers the input and hints at outputs ('bindings, controlled entities, and continuity history'). It is mostly complete but could define these terms slightly better for agents unfamiliar with the domain.

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?

The schema provides 100% coverage with a description for the only parameter 'principal_id' (e.g., format). The description does not add extra meaning beyond the schema, such as clarifying the principal ID format or how to obtain it. Baseline 3 is appropriate.

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 defines the tool's action (look up a principal) and explains what a principal is ('the enduring actor behind entities'), and specifically lists the returned data: bindings, controlled entities, and continuity history. This distinguishes it from sibling tools like ep_search_entities or ep_trust_profile.

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 implies usage when needing to resolve an entity to its principal or find historical information, but it does not explicitly state when to choose this tool over alternatives like ep_search_entities or ep_trust_profile. No exclusions or alternatives are mentioned.

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