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

Annotations declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, and the description stays consistent while adding real value: 'tamper-evident log' conveys immutability, the return of an entry_hash receipt tells the agent how to verify the write, and the API-key requirement flags auth. It stops short of covering rate limits or what happens on conflicting appends.

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, no filler, with the operation front-loaded ahead of the return-value and auth notes. Every clause carries information.

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 7-parameter write tool with no output schema, the description covers the core operation, the return shape (entry with entry_hash receipt), and the auth requirement, while the schema carries the field-level detail. Minor gaps remain around append conflicts or idempotency semantics, but the essentials are 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%, so every parameter (including enums for outcome and action_type and the 16 KB details limit) is already documented in the schema. The description adds no parameter-level meaning beyond that baseline, so a 3 is appropriate.

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 gives a specific verb and resource ('Append an action to the organization's tamper-evident log') and even characterizes the return ('entry_hash receipt'). This clearly reads as a write/append operation, implicitly distinguishing it from the read/verify/handshake siblings, though no sibling is named explicitly.

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 when-to-use guidance, no when-not conditions, and no named alternatives among the many ledger_* siblings. The only prerequisite offered is 'Requires the organization API key,' which is an auth constraint rather than usage routing.

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