_sign_data

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

With no annotations, the description carries full behavioral disclosure burden. It only says 'Sign data using ECDSA' and does not explain effects like whether data should be raw or hashed, error handling, or the role of parameters like 'deterministic' and 'sigencode'. This is insufficient for safe invocation.

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 extremely concise (one sentence), but it lacks structure such as parameter highlights or usage notes. While brevity is good, it sacrifices informativeness. A well-structured short description could include key details.

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?

Given the tool complexity (6 parameters, output schema) and lack of annotations, the description is severely incomplete. It does not explain input/output formats, required parameter details, or error behavior. This leaves the agent underinformed for correct invocation.

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 0%, and the description adds no parameter explanations. It does not elaborate on private_key format, data format, curve options, hash function, signature encoding, or determinism. The description fails to compensate for the missing schema 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 clearly states it signs data using ECDSA, which is a specific verb+resource (sign + data) and mentions the algorithm (ECDSA), distinguishing it from non-signing siblings. However, it does not clarify the difference from _sign_digest or specify input/output formats, so it is not maximally clear.

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?

No guidance is provided on when to use this tool versus alternatives like _sign_digest or _verify_signature. The description does not mention prerequisites, context, or exclusion cases, leaving the agent without decision support.

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