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

Beyond the annotations (readOnlyHint=false, openWorldHint=true), the description discloses high-value behavior: it consumes one monthly Pro quota credit (100/month), save=false returns a suggestion without writing, alt text is only written when the step lacks one, and video steps get no narration. It stops short of saying whether save=true overwrites existing title/text.

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?

One front-loaded paragraph that opens with the core action and then layers the quota, save, narration and alt caveats. It is dense but every clause carries information; the long compound sentences cost it a point versus a crisper structure.

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 generation tool with no output schema, the description covers the mutation semantics, quota cost and conditional writes that an agent needs. It does not describe what a save=false call returns, which is the main remaining gap.

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 already 86%, so the baseline is 3; the description adds real semantics on top — the side effect of the save flag ('só sugere'), the conditional alt behavior, and the video-step exception that governs narrationScript. It leaves useImage and instructions with only what the schema already says.

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 uses a specific verb+resource ('escreve título e texto do balão' a partir da captura do passo) and makes clear it is an AI generation tool distinct from update_step/add_step. It overlaps with the sibling generate_narration by noting narrationScript, but never names that sibling or tells the agent when to prefer it over this one.

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?

Usage is implied rather than prescribed: 'a IA olha a captura e escreve' tells the agent the scenario, and 'save:false só sugere' hints at a preview mode. However, there is no explicit when-to-use/when-not framing and no routing away from generate_narration or update_step, so the agent must infer the boundaries.

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