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

With no annotations, the description is the only source of behavioral information. It does disclose return contents (counts, date ranges, history_begins, known gaps) and the tool's focus on missing data. However, it does not explain how the optional publisher filter affects results, what 'tier by tier' means, or any limitations/formatting.

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 concise at two sentences and includes useful specifics in the first sentence. However, it is slightly poetic ('tier by tier') and could be more direct, but it still earns its place without unnecessary fluff.

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?

Given the tool's simplicity (1 optional parameter, no annotations, no output schema), the description provides a reasonable overview but leaves gaps: it does not clarify the meaning of 'history_begins', how publisher filtering narrows results, or the grouping by tier. More detail would improve completeness.

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 schema already documents the single optional parameter ('publisher' with description 'optional publisher id'), and schema description coverage is 100%. The description adds no additional meaning about how the publisher parameter is used, so a baseline of 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 purpose: to report coverage (what we hold and lack) with specific output types (counts, date ranges, history_begins, known gaps). It distinguishes itself from siblings by explicitly focusing on gaps (what we do NOT have).

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 implies usage for checking coverage gaps ('This tool exists to say what we do NOT have'), but it does not explicitly state when to use it versus alternatives or mention any exclusions. No sibling comparisons are provided.

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