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

Without annotations the description carries the burden, and it does disclose valuable behavior: the tx is unsigned, it is a single atomic transaction (no separate approve), and the permit is consumed by the sell (non-reusable). It omits failure modes, whether the permit must match exactly, and slippage behavior, so it adds context but not enough to fully substitute for annotations.

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 sentences, front-loaded with 'Unsigned tx' and the version/token-type qualifier. There is minimal waste, and the permit-provenance detail is packed without padding.

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?

For a build-tx tool with no output schema, the description covers what it builds and the permit provenance, but it is silent on the shape of the returned unsigned tx, the default/handling of slippagePct, and any failure prerequisites, leaving gaps an agent might need to call 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 only 20% (deadline only), so the description should compensate more. It does clarify that `amount` should equal the permit's exact amount and that `signature` is the permit signature from build_sell_tx, adding real meaning, but `token` and especially `slippagePct` remain undocumented.

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 uses a specific verb (build unsigned tx) plus resource (one-transaction sell via a Permit signature), and it identifies the source of the permit from build_sell_tx. It is clearly a permit-based variant of build_sell_tx, though it stops short of an explicit 'use this instead of build_sell_tx when X' statement.

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 useful conditions parentalhetically ('pad v2.3+, EIP-2612 tokens') and says the permit comes from build_sell_tx, which implies the prerequisite. But it never explicitly states when to choose this over the plain build_sell_tx two-step flow or what to do when a token lacks EIP-2612 support, leaving routing to inference.

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