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

Annotations only supply weak hints (idempotentHint false, destructiveHint false), but the description adds substantial undisclosed behavior: it spends credits, refusals charge nothing, failed generations auto-refund, deck-attach hiccups never refund, and placeholder-copy slides are refused at zero spend. This is exactly the extra context annotations cannot convey.

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 critical payload (cost gate, required params, approval flow) is front-loaded and every sentence carries operational content. The bold/bold-caps emphasis is slightly heavy but does not waste much space.

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 no-output-schema, 9-param, credit-spending mutation, the description covers the approval gate, refund behavior and post-call polling well. The remaining gap is the unexplained optional parameters, which leaves an agent guessing about model/resolution/characterId selection.

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 only 33% across 9 params. The description explains slideIds, maxCredits and promptOverrides semantics, but those are already documented in the schema, while model, resolution, characterId, accountHandle and idempotencyKey remain undocumented in both places. Partial compensation, not full.

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 and resource ('Generate background art for NAMED slides of a carousel deck') plus its cost-critical distinction from other deck tools. It does not, however, explicitly contrast with the sibling antix_generate_deck_background, and the claim 'the ONLY deck tool that spends credits' is ambiguous given a background-generation sibling exists.

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 explicit prerequisites and a pre-call sequence (quote backgroundCostEstimate from antix_create_deck/antix_get_deck, get explicit user approval), plus conditional routing (write copy first or use promptOverrides; poll antix_check_batch for progress). An agent knows exactly when and how to invoke it.

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