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

Annotations already declare destructiveHint=true, openWorldHint=true, idempotentHint=false, and readOnlyHint=false. The description adds meaningful context beyond them: it uses a local private key from a PK env var and is intended only for dev, with production routed elsewhere. It does not elaborate on irreversibility or failure behavior, but the annotations already carry the destructive profile.

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 concise sentences with the most important safety information first. Every sentence adds value: dev-only scope, production alternative, and input source.

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?

The tool is destructive and open-world, but the description covers the critical dev-only warning, private-key source, and production alternative. Parameter details are fully covered by the schema, and an output schema exists, so no further return-value explanation is required.

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 adds useful workflow context by saying the transaction object comes from any write_* tool, but it does not add parameter-level meaning beyond the schema.

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: sign and broadcast an unsigned transaction. It explicitly distinguishes this tool from sibling write_* tools by saying it takes their returned transaction object and submits it onchain.

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 an explicit when-to-use condition (after a write_* tool returns an unsigned transaction), an explicit when-not-to-use condition (production), and names concrete alternatives (Fireblocks, Safe, Turnkey). The DEV ONLY warning is front-loaded.

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