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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds the content scope (platform list plus safe-zone advice) but says nothing about the return shape or whether the optional filter changes the output format.

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 tight sentence, front-loaded with the core deliverable (aspect ratio and pixel size) followed by the platform coverage and the safe-zone extra. No filler.

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 zero-parameter-required static reference lookup with no output schema, listing the covered platforms and the safe-zone advice is nearly sufficient. Minor gaps: it doesn't clarify whether omitting the filter returns all platforms or a default subset.

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% and the single optional 'platform' param is fully documented in the schema with examples. The description adds no format or semantics beyond that, so the baseline of 3 applies.

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?

Names the specific resource (recommended aspect ratio and pixel size) and enumerates the exact platforms covered, so an agent knows precisely what reference data it will get. Clearly distinguishable from the sibling editor/media actions, which are all operational rather than informational.

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 by the content scope — consult this when you need platform specs — but the description never states when to call it versus simply answering from model knowledge, nor does it name any alternative. No exclusions or prerequisites given.

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