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

Goes well beyond the annotations by disclosing that creation fires the session.created webhook, is bounded by the plan's limits, and requires the mcp:write scope — the kind of side-effect and auth context annotations cannot carry. The non-destructive, non-idempotent profile declared in annotations is consistent with the text.

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?

Three tight sentences, front-loaded with the action and return value, then follow-on context and constraints. No filler.

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?

With no output schema, the description correctly states the return value (the id), and it covers auth scope, plan limits, and webhook side effects. The remaining gap is parameter meaning for name and project_id, which leave an agent guessing at call-time inputs.

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 only 33%: idempotency_key is documented in the schema, but project_id and name are bare. The description says creation happens "in a project" (loosely implying project_id) but never explains the optional name or clarifies key semantics, so it does not compensate for the coverage gap.

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?

States a specific verb and resource ("Create a video session in a project") and adds the outcome ("Returns its id"), which lets an agent distinguish it from create_connection_token and verify_session. It stops short of naming siblings explicitly, so it is clear but not maximally differentiated.

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?

"Browsers join it with connection tokens" implies the follow-up step (create_connection_token) but never states when to prefer this over alternatives or any preconditions beyond scope. Usage is inferable rather than specified.

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