sign_transaction

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

With no annotations, the description carries the full behavioral burden. It usefully discloses that keys are TEE-stored and that supplying an address bypasses HD derivation, but it never says whether the signed tx is broadcast or only returned, what the caller gets back, or what permissions/errors apply to a signing operation.

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 short sentences, front-loaded with the core action and mechanism. Slightly weakened by the redundant 'keyCode is always required' and the misleading chain-coverage claim, but overall tight.

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 7-parameter, no-annotation, no-output-schema mutation tool, the description covers key resolution and chain input formats but omits the return value, whether broadcasting occurs, and failure/permission behavior. Adequate but with clear gaps for a high-stakes signing operation.

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 baseline is 3 and the schema already documents tx, path, chain, address, chainId, keyCode and encoding. The description mostly restates required-ness and re-explains the address shortcut, and its 'SUI and other chains' claim actively conflicts with the chain enum, so it adds little net clarity.

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 a blockchain transaction') and names the mechanism ('TEE-stored key'), which distinguishes it from the sibling sign_message. However, it claims support for 'SUI, and other chains' while the schema enum only permits EVM and SOL, which muddies the exact scope of the tool.

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 in-line conditions for parameters (keyCode always required, address skips HD derivation, chain required for mnemonic keys) but never states when to choose this tool over sign_message or the other key-management siblings. Usage is implied by the name rather than guided.

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