session_info

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

Adds significant context beyond readOnlyHint and destructiveHint annotations: explains behavior per auth flow, internal API calls (profile_get vs /session-info), and provides a concrete example output.

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?

Single paragraph with efficient sentences covering purpose, usage, alternatives, prerequisites, and example. No wasted words.

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?

Complete for a parameterless tool with good annotations: describes return values, variants, prerequisite, and sibling relationship. No missing information given complexity.

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?

No parameters exist, so description naturally cannot add parameter info. Baseline of 4 applies as schema coverage is 100% and no further elaboration needed.

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?

Clearly states the tool returns session info (userId, type) with specific verbs and resources. Distinguishes from sibling profile_get by highlighting different return scope.

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?

Explicitly tells when to use (to get userId for user-scoped operations) and when not to (if more profile data needed, use profile_get). Also mentions prerequisite of valid session and alternative auth flows.

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