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

Annotations only declare readOnlyHint=false and destructiveHint=false, leaving the auth and secret-handling burden to the description — and the description delivers: 'admin' scope required, and the token is returned exactly once and must be stored. That one-time-secret behavior is a critical trait an agent could not infer from structured fields.

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 short sentences, front-loaded with the action, then the return-value caveat, then the auth requirement. Every sentence earns its place with 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 supplies the key return fact (single-use plaintext token) rather than leaving it unknown. Parameter semantics are fully covered by the schema. Minor gap: it doesn't say what a session is subsequently used for, but nothing needed to invoke it correctly is missing.

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 description coverage is 100%, so all four parameters (name, repository_id, branch_namespace, budget_cents_per_day) are already documented in the schema. The description adds no parameter-level detail beyond the auth scope, so the baseline of 3 applies.

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 precise verb+resource ('Mint a new agent-multiplayer session') that is clearly distinct from the many create_* siblings (create_branch, create_issue, create_pr) — none of those produce a session token. An agent can route to it without opening the schema.

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 gives a hard prerequisite ('Requires admin scope'), which is genuinely useful for deciding whether the call can succeed. However, it never says when to prefer this over alternatives or what condition triggers session creation, so usage is only implied.

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