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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful behavioral context by naming which pipelines' delivery times are reported, but says nothing about recency thresholds, staleness semantics, or return shape.

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?

A single dense sentence with the subject front-loaded, zero filler, and the key enumeration placed after the core noun phrase. Every clause earns its place.

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 no-arg, read-only tool with no output schema, the description is nearly sufficient: it says what is measured and by which sources. It could add how freshness is expressed (timestamps vs. lag) but the omission is minor.

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?

The tool takes zero parameters, so the schema carries no parameter meaning for the description to augment. Baseline 4 applies; the description's list of sources is the only parameter-like dimension and it is handled.

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 names a specific resource (per-source data freshness receipts) and enumerates the exact pipelines covered (OONI, IODA, CensoredPlanet, probes), plus the semantic payload ('when each pipeline last delivered'). It is clear what the tool returns, though it does not explicitly distinguish itself from the closely named sibling get_measurement_freshness.

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?

There is no statement of when to call this versus alternatives, nor any prerequisites or exclusions. Given the near-identical sibling get_measurement_freshness, the absence of routing guidance is a real gap.

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