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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful context beyond that: immutability of versions, explicit publisher cancellations, distinct publisher clocks, and importantly the auth requirement (API key, subscription_required with a subscribe link).

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?

Purpose is front-loaded in the first sentence, but the second sentence ('Capture, acceptance and documentary publisher clocks remain distinct') is opaque jargon that does not clearly earn its place. Dense but not bloated overall.

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?

An output schema exists, so return values need not be explained. The description covers immutability, cancellation semantics, pagination state, and access requirements, leaving little an agent needs in order to call it correctly.

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 the schema already documents all five parameters, establishing a baseline of 3. The description adds marginal context on checkpoint/cursor pinning, but nothing about the required currency or archive_event_id beyond what the schema states.

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 ('Return') and resource ('immutable schedule and importance versions for a stable archive event ID'), which an agent can distinguish from calendar_snapshot or release_calendar. The phrasing is jargon-heavy ('source capture evidence', 'publisher clocks') but the core retrieval purpose is clear.

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?

The description says checkpoint/cursor pin subsequent history pages, which implies pagination usage, but it never states when to choose this over siblings like calendar_snapshot, calendar_archive_coverage, or release_calendar. No exclusions or alternative-routing guidance is provided.

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