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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses critical behavior: the command blocks until user approval/rejection/timeout, prints one JSON line, and exits; expected_keys tells which result field to read; Solana returns a different signer with the same shape and requires POSTing to /v1/svm/execute. This is rich, non-obvious behavioral context that annotations alone would not provide.

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?

The description is long but every sentence carries high-signal operational detail. It is front-loaded with the core purpose, then flows into agent instructions, EVM behavior, and Solana behavior. There is no filler or repetition of schema content.

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?

Despite having no output schema, the description fully explains the return behavior: one JSON line, expected_keys values (txHash, signature, signedTransaction), and the follow-up POST for Solana. It also covers blocking behavior, chain-specific differences, and the private-key handling rule, making it complete for a complex tool.

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 the baseline is 3, but the description adds meaningful parameter semantics: it explains EVM step types (approve/transaction/signature), Solana's lack of steps[] and approve, the exact step shape to pass for Solana, and the significance of executionRef absence. This goes beyond the schema's field-level descriptions.

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 states a specific verb and resource: it 'synthesizes the local CLI signer invocation for one step of a swap_build plan' and explicitly distinguishes itself by noting it 'does not call the Vurto backend'. This clearly separates it from backend-calling siblings and makes its role unambiguous.

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?

The description gives explicit operational guidance: the agent must not ask for a private key, should run the command as a background task, and should never ask the user 'did you sign?'. It also clarifies when EVM vs Solana parameter shapes apply. It does not name sibling tools as alternatives, but the context is clear enough for correct use.

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