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

Annotations only flag non-read-only, idempotent and destructive; the description adds substantive context beyond them: the decision is a one-shot exception consumed by the next ledger_track rather than a raised cap, only pending permits are decidable, and the credential separation model. It does not contradict idempotentHint — re-deciding an already-decided permit is a no-op.

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, each carrying distinct content: the action and its scope, the authority separation, and the consumption semantics. The key constraint (owner-only) is front-loaded in the first line.

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?

Output schema exists, so return values need no explanation here. For a destructive, non-idempotent-looking mutation the description covers authorization, valid inputs, state requirements and post-decision consequences — everything an agent needs before invoking it.

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 agent_id, approval_id, decision and workspace_key are already documented with their meanings. The description restates the 'approve'/'deny' enum for decision and adds the 'pending permits only' constraint, but contributes no format or sourcing detail beyond the schema. Baseline 3 is correct when the schema does the heavy lifting.

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 pair and resource ("Approve or deny a pending spend permit") and immediately scopes it ("workspace owner only"). It also implicitly separates itself from the sibling ledger_request_approval by explaining that requesting and deciding are different authorities, so an agent can pick the right tool without opening schemas.

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 names the precondition (only pending permits can be decided), the authorization requirement (workspace owner only), and the alternative path (agent_secret can REQUEST via ledger_request_approval but never decide). When/when-not and the alternative are all present.

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