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

With no annotations, the description carries the full burden and does well: it discloses the return shape (typed_data, or approval_state=pending under human_passkey), the permission prerequisites, and the critical non-custodial guarantee that MCP alone can never move funds. It does not cover whether preparation reserves or locks funds, typed_data expiry, or idempotency of repeated calls.

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 tight clauses, each earning its place: what it does, what it requires/returns, and the execution boundary. The safety-critical constraint is front-loaded and no sentence is 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?

For a two-parameter preparation tool with no annotations and no output schema, the description covers prerequisites, the return contract, and the execution boundary that an agent most needs to avoid overclaiming success. The remaining gap is destination/amount format, which is the one thing an agent could get wrong at call time.

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 0%, so the description must explain both parameters, and it largely does not. "destination" has no stated format (Arbitrum address? wallet id? label?) and "amount_usd" only gains the implicit hint that USD is converted to USDC — no minimums, precision, or rounding semantics are given.

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 and resource ("Prepare a withdrawal"), the asset and chain path (USDC → Arbitrum), and clearly separates itself from the sibling that actually executes (submit_intent). An agent can identify both what it produces and what it does not do 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?

Gives explicit prerequisites (withdraw scope + matured allowlist) and names the alternative for the execution step (submit_intent via wallet signature), plus the human_passkey branch that yields approval_state=pending. The when-to-use and when-not-to-expect-execution conditions are both spelled out.

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