pixoo_overlay_text

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

The description adds behavioral context beyond annotations: 'Overlays use device-rendered fonts...', 'persist across channel switches until explicitly cleared', and 'Not previewable — rendering happens on-device.' Annotations (destructiveHint=false, idempotentHint=true) are consistent and supplemented.

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 five sentences, front-loaded with the core purpose, and contains no redundant or extraneous information. Every sentence adds value.

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 a well-covered schema (11 params, 100% description in schema), annotations, and an output schema (context indicates exists), the description completes the picture by explaining persistence, on-device rendering, and the alternative tool. No gaps remain.

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 baseline is 3. The description adds value by explaining font ID ranges and examples (e.g., 18=arrows, 20=°C/°F) and clarifying overlay slot behavior. However, it does not elaborate on all parameters beyond schema.

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 explicitly states the verb-resource pair: 'Set or clear a device-native scrolling text overlay.' It also distinguishes from the sibling tool pixoo_display_text, which is for styled, previewable text.

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?

The description clearly states when to use ('Best for persistent tickers over pushed scenes') and when not ('for styled, previewable text use pixoo_display_text instead'), providing an explicit alternative.

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