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

The readOnlyHint annotation already flags this as a safe read. The description adds meaningful behavioral context: weekly refresh, composite z-score methodology, and the exact fields returned. It doesn't contradict annotations, but doesn't go into pagination or the history query behavior (which is covered in the param schema).

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?

Three sentences: output definition, use cases, refresh cadence. Every sentence carries distinct information and is front-loaded with the most critical details. No wasted words.

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 bulk data tool with one optional parameter and no output schema, the description covers output contents, scope (~619 vendors), update frequency, and appropriate invocation contexts. It lacks ordering/filtering details, but the use cases and schema are sufficient for an agent to invoke 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?

The sole parameter 'days' is fully documented in the schema with 100% coverage (history series, Gold tier requirement, fallback behavior). The description doesn't duplicate or augment this, so it adds no extra param semantics beyond the baseline provided by 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?

The description opens with a specific verb ('Returns'), defines the output (0-100 positioning score for ~619 vendors), the composite methodology (z-score across vision and execution), and lists the returned fields (vision_score, execution_score, drivers, methodology_version). This clearly distinguishes the tool's purpose from sibling tools.

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?

Explicitly states 'Call when...' followed by five concrete use cases (vendor positioning, shortlists, landscape comparisons, vendor selection, renewal, partnership timing). This provides clear when-to-use guidance, though it doesn't name alternative tools for exclusion or state when not to use.

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