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

Goes well beyond the readOnlyHint/openWorldHint annotations: it explains the underlying append-only sha256 hash-chain structure, that the value is null on an empty record, and that no credentials are required. These are exactly the operational details an agent needs to interpret the result confidently.

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 tight sentences: what is returned, what it means cryptographically, and how to use it later. The essential identity of the return value is front-loaded, and the free/no-credentials note is a useful trailing qualifier rather than filler.

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 no output schema and no parameters, the description must carry the return-value explanation, and it does: latest entry id, hash, and null-on-empty. Annotations cover the safety profile, and the description covers everything else an agent needs to call and interpret it correctly.

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?

The tool takes zero parameters, so the baseline is 4 — there is nothing for the description to disambiguate about inputs. It correctly spends no words on parameters and instead invests in explaining the returned head value.

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?

States a specific verb+resource — returns the latest entry id and hash of the public record — and immediately qualifies the record as an append-only sha256 hash chain (hash_v1). An agent can distinguish this checkpoint tool from muhabbit_record_entries and muhabbit_record_verify without opening any schema.

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?

"Pin the head now; muhabbit_record_verify later proves nothing up to it was rewritten" gives explicit sequencing and names the complementary tool, so the agent knows the pin-then-verify workflow. It never states when NOT to use it (e.g., to enumerate entries use muhabbit_record_entries), so it falls short of full alternative routing.

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