download_reels

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

No annotations, description bears full burden. Discloses return format, quality, and error condition (private accounts). No mention of rate limits or other side effects, but sufficient for a simple download tool.

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 sentences, front-loaded with purpose, no redundant 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?

Given one parameter and no output schema, description covers what is returned, format, quality, and error handling. Complete for this tool.

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 has 100% coverage for the single 'url' parameter. Description adds value with example URL format, aiding correct input.

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?

Clearly states 'Download an Instagram Reel from a public post URL' with specific output details (original 9:16 HD MP4, no watermark, no re-encoding). Distinct from siblings like download_story.

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?

Explicitly states public accounts only, private accounts return HTTP 422. Could mention alternative tools for other Instagram content but usage condition is clear.

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