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

Annotations cover safety (idempotent, non-destructive, open-world), but the description adds genuinely non-structured behavior: it refuses and returns candidates rather than guessing when the place/language is ambiguous, and it updates an existing market for that location instead of creating a duplicate. Auth/permission requirements are unstated, and idempotency is only implied by 'updated'.

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 primary action, then the ambiguity fallback, then the update semantics, then a compact scope boundary and related-tool list. Every sentence carries distinct information; nothing is repeated from the schema or annotations.

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 annotations and an output schema present, the description need not restate safety or return values, and it covers the resolution behavior and the ambiguous-input path. The main residual gap is the absence of any permission or account-precondition context for a tool that writes a market definition.

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% and every parameter already carries a description, so the schema does the heavy lifting. The description adds the notion that place/language are resolved to DataForSEO codes and that ambiguity is surfaced, but says nothing about priority or timezone semantics 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 pair (creates/updates) and resource (an active market) plus the transformation it performs: resolving DataForSEO location and language codes. The 'Does not start a rank check' clause and the Related list separate it from run_rank_check and the read-only market 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?

Gives a clear precondition (place + language, with an ambiguity fallback that refuses and returns candidates) and an explicit non-use case (it does not start a rank check). Sibling routing is only a bare 'Related:' list without conditions, so it stops short of full when/when-not guidance.

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