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

Annotations already indicate destructive and non-read-only behavior; the description adds valuable context by flagging DEV ONLY, mentioning the local private key env var, and clarifying this is the final onchain submission step. It does not go deeper into failure modes, but the annotation coverage plus dev-only warning cover the most important safety context.

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 focused sentences with no filler. The most important constraint (DEV ONLY) is front-loaded, the production alternative is stated, and the input source is clarified. Every sentence earns its place.

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?

With a rich schema, output schema, and annotations, the description covers what the tool does, when to use it, when not to use it, and where its inputs come from. Nothing essential for selecting or invoking the tool correctly is missing.

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 documents to, data, value, and chain_id. The description points to the source of these values (a write.* tool result) but adds no parameter-level semantic detail beyond what the schema provides.

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 is explicit: sign and broadcast an unsigned transaction using a local private key. It names the resource (an unsigned transaction from write.* tools) and the action (submit onchain), and the DEV ONLY prefix clearly separates it from the read_/write_ sibling tools.

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 states when to use the tool (after any write.* tool returns a transaction object) and explicitly warns against production use, naming alternatives (Fireblocks, Safe, Turnkey, etc.). This gives an agent clear routing guidance.

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