sign_message

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

With no annotations, the description carries the full burden. It usefully discloses that the signing key is TEE-stored and that supplying an address bypasses HD derivation, but it omits what is returned (signature encoding/format), whether any unlocking or authorization is required, and any rate-limit or failure behavior.

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, front-loaded with the operation and its most surprising constraint (hash input), followed immediately by the required/optional parameter summary. No wasted words.

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 cryptographic signing tool with no annotations and no output schema, the description should explain the signature result format or at least confirm return shape. It covers the input contract well but leaves the outcome and any authorization requirements unstated.

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%, so the schema already explains path, chain, address, keyCode, and message. The description only restates the required/optional status of keyCode and address, adding the "skip HD derivation" rationale for address but nothing beyond the schema's own wording.

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 ("Sign an arbitrary message") and adds the critical constraint that the payload is a hex-encoded sha256 hash, which cleanly separates it from sign_transaction. It does not, however, name or rule out any sibling explicitly.

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 clarifies the keyCode/address interplay ("keyCode is always required", "Optionally provide address to skip HD derivation"), which implies how to call it. But it never says when to choose this over sign_transaction, nor any prerequisites such as key state or permissions.

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