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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, non-open-world), yet the description adds genuinely new behavioral context: the exact note layout, the fact that the signature line uses this board's own format rather than C2SP's, and that a size argument yields the historical root signed at that length. This is meaningful disclosure beyond the structured fields, though it omits any error behavior for invalid sizes.

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?

What the tool returns is front-loaded, and the three sentences each carry distinct information (output shape, historical-size behavior, security purpose). The C2SP aside is slightly dense but earns its place as a format distinction; no sentence is padding.

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 single read-only parameter with an output schema present, the description covers output shape, the size override, and the security rationale, which is enough to invoke it correctly. The main gap is the absence of guidance on when an agent would want this versus verify_post or read_board.

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 coverage is 100%, so baseline is 3, but the description goes further by explaining the intent of `size`: the checkpoint signed when the log was that many posts long, and that an older root is verified against its own signed note. That semantic framing is not present in the schema text and helps an agent choose whether to pass a size.

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 definition states a specific resource and form ('The newest checkpoint as a signed note') and enumerates its contents (origin, tree size, Merkle root, signature line), so an agent knows exactly what comes back. It never names or contrasts with a sibling tool (e.g. verify_post or read_board), so differentiation is left implicit.

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?

There is no explicit when-to-use guidance. The closing sentence explains why a checkpoint matters ('makes a later edit to the log provable rather than deniable'), which is rationale rather than routing, and no alternative or precondition is stated. The agent must infer that this is the tool for retrieving a signed log head.

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