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

With no annotations provided, the description carries the full burden, and it delivers: it discloses the sorting order (newest first), the default window (last 30 days), the fields returned (last_confirmed, stale), the freshness summary contents, and that it is free/unmetered. Nothing contradicts the annotations because there are none.

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?

The description is front-loaded with the core purpose and contains valuable routing and alternative instructions. It is slightly wordy with promotional flourishes like 'Freshness is checkable or it is marketing' and redundant pricing details, but overall it is organized and each major sentence serves a purpose.

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 read-only feed tool with one optional parameter and no output schema, the description is complete: it explains the default behavior, return contents, freshness summary, usage timing, and alternative tools. An agent has enough to select and invoke this tool 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 fully documents 'since' with format and default. The description only restates 'Args: since? (YYYY-MM-DD)' and adds usage context rather than new parameter-specific semantics, so baseline 3 is appropriate.

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 clearly states the tool's function: it returns changed series since a given date plus a dataset-wide freshness summary. It explicitly distinguishes itself from siblings by saying 'Do not re-pay get_series to discover a diff' and by naming alternatives like register_alert and the certified endpoint.

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 gives explicit when-to-use guidance: 'After any paid series or answer call, call this before you assume the cached value is still the law.' It also provides exclusions and alternatives: do not use get_series for diffs, use register_alert for push, and use the certified endpoint for a filing freeze.

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