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

No annotations are supplied, so the description carries the full behavioral burden. It usefully discloses that the tool is optional and redundant on the standard v4 route, but says nothing about what it returns, whether it requires signing, or what happens with the token approval — a notable gap for a prepare-type tool with zero annotation coverage.

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?

Two tight sentences, zero waste, with the 'optional helper' framing and the routing exclusion front-loaded before any detail. Well sized for the amount of information conveyed.

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 and no annotations, the description should ideally describe the return artifact and any signing/approval prerequisites. It covers when-to-use thoroughly but leaves what the agent gets back and what to do with it unspecified, making the definition only partially complete.

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% — both 'token' and 'permitData' are documented in the schema. The description adds no syntax, format, or normalization detail beyond that, so the baseline 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?

The description names the resource (Permit2 approval) and its role as a helper, and explicitly distinguishes itself from stocktoken_execute_plan. It is clear enough to route against siblings, though it never states what the tool actually produces (unsigned approval payload vs. typed data).

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 states the exact condition for use ('only when you are assembling a plan by hand') and names the alternative that makes it unnecessary (stocktoken_execute_plan, which already includes the Permit2 approval on a v4 route). No inference is required.

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