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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), but the description adds two traits not in structured data: the cost model ('Paid per call via x402') and the privacy guarantee that raw actions are not exposed. It stops short of stating failure modes (e.g. behavior on an empty or missing stream) or rate limits.

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 sentences, front-loaded with the core purpose, then the enumerated outputs, the privacy boundary, and the cost note. With no output schema, the field enumeration earns its place rather than 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?

With no output schema, the description usefully documents the returned fields, the non-disclosure boundary, and the per-call payment — enough for an agent to call it correctly. It is slightly thin on edge-case behavior (tampered vs intact output shape, empty streams), which keeps it from a 5.

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 only org_id and stream_id, both documented in the schema itself (including the 'stream_id is usually the agent's name' hint). The description adds no extra parameter meaning beyond linking the call to 'an agent's action log', so the baseline 3 applies.

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 ('Check whether an agent's action log is intact') and enumerates exactly what is inspected: entry count, time span, action/failure counts, head hash, and where the chain broke. The clause 'Does not reveal the actions themselves' implicitly distinguishes it from the action-revealing sibling ledger_read_stream, so an agent can separate the two without opening either 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?

Usage is only implied — an agent can infer this is for integrity verification after actions are recorded, but there is no explicit 'use this when...' framing and no sibling alternative (e.g. ledger_read_stream, ledger_verify_report) is named as the choice for a different need. The privacy clause hints at a boundary but does not state the routing condition.

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