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

Annotations already declare readOnlyHint=true and openWorldHint=false; the description reinforces this ('does not store it or sign it') and adds genuinely new context: a hard cost of 5 prepaid credits and a production billing requirement. What it omits is whether computation is deterministic/pure and whether chains must be built sequentially, but the added billing and no-side-effect disclosure is real value beyond annotations.

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 tightly written sentences with the core behavior front-loaded and no filler. The billing note is compressed into a terse fragment, which is efficient but slightly telegraphic.

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 tool with an undocumented nested object and no output schema, the description should explain what the computed entry contains and how 'previous_sha256' chains to prior output; neither is covered. Combined with zero parameter documentation, an agent lacks enough to construct a valid call confidently.

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 0% and the description says nothing about either parameter. The nested 'action' object is typed only as a generic object with no documented fields, and 'previous_sha256' format/ordering semantics (genesis value, prior entry hash) are unstated, so the description fails to compensate for the coverage gap.

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 states a specific verb and resource ('Compute a hash-chained entry') and immediately narrows scope with 'does not store it or sign it', which contrasts it with a verify/persist sibling. It never names the sibling (privi_pro_action_chain_verify), so the differentiation is inferred 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?

Usage is only implied: the negative scope ('does not store it or sign it') hints at when this is appropriate versus a storing/verifying tool, but no explicit when-to-use, prerequisites, or alternative is named. An agent must guess where this sits in the chain workflow.

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