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

Annotations already indicate readOnly, idempotent, and non-destructive behavior. The description adds valuable beyond-annotation context: GPU acceleration, tiled processing at 256x256 to manage VRAM, and the maximum output dimension of 8192x8192. This gives the agent a realistic sense of computational constraints and edge cases.

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 well-structured with an opening summary, useful technical constraints, and clearly formatted Args and Returns sections. The first two sentences are slightly redundant ('Upscale image resolution' and 'Enhances image resolution'), but overall every section earns its place given there is no output schema.

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 no output schema, the description fully documents the return dict keys. It also covers input formats, scale factor options, the default scale, tile processing, and output size limits. For a two-parameter, read-only tool, nothing essential is missing for an agent to call it correctly.

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 schema already documents both parameters. The description repeats the same parameter information without adding significant new meaning, though the maximum output dimension is a useful context clue. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 specific verb and resource: 'Upscale image resolution with the Brainiall image-upscaling engine.' It clearly states the tool's function, scale factors (2x or 4x), and distinguishes it from sibling image tools like remove_background and restore_face.

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 intended use is implied by the description — use when you need to upscale an image — but there is no explicit when-to-use guidance, no exclusions, and no mention of alternative tools. It provides useful operational context like the 8192x8192 output limit, but stops short of guiding tool selection.

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