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

With no annotations, the description carries the full burden and does so well: it discloses first-party credentials, zero credit cost, the fixed rolling-snapshot caveat for position/CTR that is never window-matched, and that days_covered can be shorter than requested. Pagination semantics (truncated, next_offset, per-list paging) are also spelled out.

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 purpose and the sibling contrast, then moves to caveats and paging. It is on the long side and the PAGING block partly restates the schema's offset description, but every sentence carries operational value.

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?

No output schema exists, yet the description explains the return shape (metrics fields, top queries/pages lists, pagination block with returned/total_available/truncated/next_offset) and warns against drawing totals from truncated slices. An agent has everything needed to call and interpret it.

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%, so the baseline is 3, but the description adds meaning beyond the schema: it clarifies that limit and offset apply to both returned lists and that each list gets its own pagination entry and next_offset. It does not add much on site_id or days 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 ('Read') and a specific resource set (clicks, impressions, CTR, average position, top queries, top pages) scoped to the caller's own connected Bing Webmaster property. It also explicitly distinguishes itself from the Bing_Keyword_* siblings by naming the different question they answer.

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?

Gives an explicit when-to-use rule ('whenever the question is about how a site the caller owns is actually performing on Bing') and names the alternative tools plus the condition that selects them (third-party estimates, cost credits).

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