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

Adds a lot beyond the annotations: a write-permission requirement, the preview/confirm/previewToken handshake with a 15-minute single-use token, the cost model (prompts × runs × engines, premium engines 3×) and a side effect (internal timeline note). The one gap is that it doesn't say whether omitting confirm ever mutates anything implicitly -- though the preview statement largely covers that.

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?

Dense but front-loaded: the core definition comes first, then defaults, then the scan-cost and confirm mechanics. The final sentences run long and pack several distinct facts (cost formula, first scan timing, write permission, timeline note) into one breath, but nothing is filler.

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 7-parameter mutation with no output schema, the description covers the two-step confirm flow, defaulting behavior on both optional arrays, cost implications, and a side effect. An agent can call it correctly and knows what to expect in return (a preview).

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; the description earns above that by explaining what omitting `prompts` or `competitors` does (empty market vs inherited project list) and clarifying that a market's own competitors only scope its share-of-voice measurement. It still defers to the schema for the locale syntax and token lifetime.

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 (add) and resource (a market) and pins down what a market actually is: a country+language or language alone with its own prompts and competitors. That framing distinguishes it from every sibling mutator (add_tracking_prompt, manage_competitors, translate_prompts) without needing the schemas.

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 frames the preview-vs-apply workflow ("without confirm:true it returns a preview") and points at translate_prompts as the upstream source for prompt texts. It doesn't say when to choose this over add_tracking_prompt for an existing market, so it stops short of naming alternatives.

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