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

Annotations already establish read-only and non-destructive behavior. The description adds meaningful behavior beyond that: the payload is exact UTF-8 bytes, signing uses an optional Ed25519 key, and failure to sign does not invalidate the snack. This gives the agent a clear behavioral model.

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 concise sentences, no filler, with the core behavior stated first and the optional-signing caveat second. 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?

Given the rich input schema, output schema, and read-only annotations, the description covers the essential behavior. The only notable omission is guidance for choosing between this tool and related sibling signing tools, but the core context needed to call it is present.

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%, with both snack_id and agent_token already well-documented, so the description need not add parameter details. It does not compensate with extra semantics, but the schema carries the load adequately.

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?

Description uses a specific verb ('Return') and names the resource ('snack signing payload'), with clear intent: produce UTF-8 bytes for the connected agent to sign. It is clear what the tool does, though it does not explicitly differentiate itself from sibling tools like get_root_signing_payload or sign_snack.

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 note that 'the snack remains valid if unsigned' gives useful context about when signing is optional, and implies this payload tool is a pre-signing step. However, it does not explicitly compare against alternatives such as sign_snack or get_root_signing_payload, so usage guidance is mostly implied.

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