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

With no annotations, the description must carry the behavioral burden. It discloses the output structure (entries with fields s, b, r, t), the hash-chain formula, and the binding semantics. It also notes the tool is 'Public on every lane,' implying a public read operation. It does not explicitly state read-only status or failure modes, but the read-oriented purpose and public nature are strongly implied. The description adds substantial context beyond the schema.

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 a compact two-sentence definition: the first sentence covers the range and data structure, the second the use case. There is no filler or redundancy; every sentence contributes essential information. It is front-loaded with the core behavior and then explains the purpose.

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 description explains the return format and the hash-chain purpose, which is good for a simple tool with no output schema. However, it does not define what 's' and 't' in {s, b, r, t} represent (only b and r are explained). An agent might need to know if 's' is the sequence number and 't' is a timestamp. Without these definitions, the agent cannot fully interpret the returned entries, creating a meaningful gap in completeness.

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%; the schema already explains 'from' (first seq, default 1) and 'limit' (1-20, default 20). The description adds context by mentioning 'Up to 20 entries from seq `from`', reinforcing the range semantics, and explains the entry structure, but does not add new parameter-specific meaning beyond what the schema already provides. Baseline 3 is appropriate since the description does not fully compensate for any gaps (there are none).

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 precisely states the tool's action: it returns up to 20 hash-chained entries {s, b, r, t} from a given sequence number. It explicitly defines the fields (b binds slot|meta|kemPub|ts, r = sha256(prevRoot + b)) and clearly distinguishes the range-query nature from the sibling null_witness_head (which likely targets a single head entry). This is a specific verb+resource with clear differentiation.

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 description implies when to use it: 'Replay the chain from a head you trust to prove a mailbox binding was never silently swapped.' This gives a concrete use case and indicates that the tool is for verification of binding integrity. However, it does not explicitly contrast with alternatives like null_witness_head or null_transparency, nor does it state when not to use it. Context is clear but exclusions are absent.

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