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

Annotations already declare readOnly/openWorld/non-destructive, so the bar is lower, yet the description adds real value: the API-key requirement and the specific subscription_required anonymous response, plus the caveat that empty results do not prove absence of events. The checkpoint/cursor sentence largely restates schema parameter docs, which keeps this from a 5.

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?

Front-loaded with the core action, then modes, then filter ordering, pagination, caveat, and auth. Dense but every sentence carries operational information; only the checkpoint/cursor sentence is partly redundant with the schema.

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?

With an output schema present and annotations covering the safety profile, the description still supplies everything an agent needs: auth behavior, mode semantics, filter-ordering, pagination mechanics, and a caveat about interpreting empty results.

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 coverage is 100% (baseline 3), and the description adds meaning beyond the schema by defining the accepted-vs-reconstruction distinction and by stating that scheduled-date and event filters apply after version selection, which the schema does not convey.

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 and resource ('Return persisted economic-event schedules, importance and cancellation states') scoped to an explicit historical cutoff, which cleanly separates it from live-calendar siblings. The knowledge_mode sentence further pins down what 'snapshot' means.

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 knowledge_mode explanation ('accepted mode requires actual capture and parser acceptance... reconstruction additionally admits qualified official notices recovered later') tells the agent when each mode is appropriate. It stops short of naming sibling tools or explicit when-not-to-use conditions, so it is not a 5.

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