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

Beyond the readOnlyHint annotations, it discloses output ordering (highest volume first), the returned fields (avg monthly searches, 12 monthly counts, suggested bid, competition, relevance), and a data-freshness caveat that volumes are estimates lagging about three days. That freshness/estimation behavior is exactly the kind of thing an agent cannot infer from structured fields.

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?

Four compact sentences, front-loaded with capability then constraints then caveats, with essentially no filler. The market-availability sentence is dense but each clause carries information the agent needs.

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 no output schema, the description fully compensates by enumerating returned fields, sort order, and freshness semantics, and it flags the location requirement and market limits. Nothing an agent needs to call this correctly — aside from sibling routing — is missing.

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 baseline is 3; the description earns more by explaining where locationIds come from (Microsoft's Geographical Location Codes list) and why multiple locations change results, which the schema only hints at with 'Required on a connected account.' It does not add anything on limit or language beyond the schema.

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?

Opens with a specific verb+resource ('keyword ideas') and names the exact inputs (up to 20 seed words) and returned metrics, so an agent can tell this is a research/discovery tool rather than a keyword-listing tool like msads_get_keywords. It never names a sibling alternative, which keeps it just short of a 5.

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?

It gives a concrete usage precondition — locationIds must be Microsoft's numeric ids because volumes are per location — and states the supported markets (US, UK, CA, AU, FR, DE), which tells the agent when this call is viable. There is no explicit 'use X instead' routing against generate_keyword_ideas or bing_keyword_research.

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