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

Goes well beyond the annotations: it discloses that the call returns UNSIGNED transaction data, is simulated first and refused if it would revert, takes effect only in the next transaction, and never signs or sends. This resolves the apparent tension between 'stop' and readOnlyHint/destructiveHint=false by making the prepare-only nature explicit.

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 and scope, followed by timing and safety semantics. 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 usefully characterizes the return as unsigned transaction data and warns of simulation refusal. It leaves open the exact payload shape and the required follow-up signing step, but an agent has enough to invoke it correctly.

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 100%, so baseline is 3; the description adds real value by stating the mutual exclusivity between a single sessionKey and the 'all: true' switch, which the schema does not express. It does not clarify what happens if neither is supplied.

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 (stop/revoke) and resource (session key), plus the two modes of scope (single key vs all). An agent can distinguish it from prepare_mandate_grant_session without inspecting either 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?

It gives a selection rule for the scope flag ('all: true' for every key), which is genuine usage guidance. But it never says when to prefer this over siblings or what preconditions must hold (e.g. that account is required, or that a signing/sending step must follow).

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