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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe-read profile is covered. The description adds genuinely new behavioral context: the proof is verifiable offline against the signed tree head, it reveals no entry contents (a privacy guarantee), and it is free. That goes beyond what the annotations convey.

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/fragments with zero waste, front-loaded with the core purpose. The privacy and cost facts are appended efficiently rather than padded.

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 read-only proof tool with no output schema, the description covers what is returned (a Merkle audit path), how it can be used (offline verification against the signed tree head), and the privacy/cost profile. What is missing is how the agent obtains the required entry_hash or how it routes to verification siblings, but the core calling information is 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 both entry_hash ('64-hex entry_hash (an action receipt)') and tree_size ('omit for latest') are already fully documented in the schema. The description adds no parameter-level detail beyond that, 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: a 'Merkle audit path proving an entry is in Privi's append-only transparency log (RFC 9162)'. An agent immediately knows this returns an inclusion proof, not a consistency proof or a receipt check. However it never names the adjacent sibling (ledger_consistency_proof) that could be confused with it, so the differentiation is implicit rather than explicit.

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?

No when-to-use, when-not-to-use, or alternative routing is given. The description notes offline verifiability and cost, but says nothing about when an agent should call this versus ledger_check_receipt, ledger_consistency_proof, or ledger_tree_head. The only usage hint ('omit for latest') lives in the schema, not the description.

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