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

Adds significant behavioral details beyond annotations: cost ($0.02 per call, x402), output size, automatic text wrapping, three themes, custom accent, and returns both PNG and SVG. No contradictions.

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?

Two dense sentences with no fluff. Front-loaded with core purpose and output, then details. Every phrase 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?

Covers all key aspects: input parameters with constraints, output format, cost, pairing with check tool. Suitable for tool with output schema and moderate complexity.

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?

Enriches schema with practical constraints: title max 140 chars and wraps to 3 lines, theme options enumerated, accent as hex, domain position, subtitle as supporting line. Schema coverage 100% but description adds value.

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?

Description clearly states it's a social card generator for OpenGraph cards, specifying output format (1200x630 PNG+SVG) and input parameters. Differentiates from sibling get_og_check by mentioning pairing pattern.

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?

Provides use context ('Pairs with /api/og/check: check the page, then generate the missing card') but does not explicitly state when not to use or compare to alternatives among many siblings.

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