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

With only readOnlyHint=false and destructiveHint=false in annotations, the description carries the full behavioral burden and meets it thoroughly. It discloses that it is free but limited by credit, returns a watermarked low-res preview, reports remaining credits, and alters behavior on purchased jobs (adds alternates, or refuses). This goes far beyond the minimal annotation hints and provides no contradictions.

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?

The description is long but dense, front-loaded with the core purpose and then structured into cost, return type, purchase flow, and tier-specific behavior. Each sentence carries distinct information, and the length is proportional to the behavioral complexity. It could be tightened slightly, but it remains well-organized and readable.

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?

Given the tool's complexity (multiple purchase tiers, credit limits, return format) and the existence of an output schema, the description covers every aspect an agent needs: what it does, what it returns, how credits work, when to use buy_logo_variation, and how behavior changes on purchased jobs. No critical gap is left to inference.

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 description coverage is 100%, so the baseline is 3, but the description adds meaning beyond the schema by explaining that 'count' is 'capped by the free-preview credits remaining on this job' — a constraint not in the schema. It also ties jobToken to generate_logo's output. These additions justify a 4.

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 precise verb+resource: 'Generate alternate style directions for an existing generate_logo job.' It clearly distinguishes itself from generate_logo (which creates the original) and buy_logo_variation (which purchases), and it names the prerequisite job. The free-preview credit note reinforces its specific role among siblings.

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 explicitly states when to use this tool versus alternatives: 'Before any purchase, each result's variationId can be passed to buy_logo_variation to purchase that design instead of the original.' It also explains the conditional behavior on different purchase tiers (COMPLETE adds alternates, other tiers refuse), giving clear when-to-use and when-not-to-use guidance, including a pointer to get_logo_result for retrieval.

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