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

Annotations already cover readOnly/idempotent/non-destructive, so the description's added value is the tier gating with a named error code and the disclosure of what the payload contains (entry_hash, prev_hash for integrity verification). 'Read-only' largely restates readOnlyHint=true, but it does not contradict it.

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 tightly packed sentences, front-loaded with the action and payload, then the gating condition and safety note. No filler.

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 five-parameter, output-schema-less export tool, the description covers purpose, payload contents, precondition, and error behavior. It leaves return shape and pagination unspecified, though the hash-chain field names give indirect notice of the response structure.

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 all five parameters are self-documenting, including the RFC3339 bounds, format enum, and incremental-pull guidance. The description adds no parameter-level detail beyond that, which is the expected baseline when the schema does the work.

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?

Specific verb (export) plus resource (tamper-evident audit log) and scope (hash-chain fields for SIEM verification). It is clearly distinguishable from the read-oriented sibling mailbuttons_audit_tail because it describes a verifiable bulk export rather than a tail view.

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?

Names the target consumer (SIEM), states the Business-tier precondition and the exact failure mode (`siem_export_not_enabled`), and hints at incremental use via the schema's high-water-mark note. It does not explicitly say when to prefer this over mailbuttons_audit_tail, so it stops short of full alternative routing.

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