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

With no annotations provided, the description carries the full transparency burden and does well: it discloses credit cost, that failures and empty results are not charged, and the cache hit behavior. It could add more about failure conditions or privacy restrictions, but the current information is genuinely useful beyond the schema.

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?

Three short sentences, each adding distinct value: core purpose, pricing/failure policy, and cache behavior. No filler or redundancy; the most important information is front-loaded.

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 tool with no output schema and no annotations, the description adequately covers the return shape, cost, failure charging, and caching. The language parameter is left to the schema, which fully documents it. This is sufficient for an agent to select and call the tool correctly in most cases.

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 url, cache, and language. The description does not add meaning beyond the schema — it mostly repeats the cache behavior. This meets the baseline but does not go further.

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 states a specific verb and resource: 'Get an AI summary of any Instagram Reel' and defines the output as 'a short paragraph plus key points.' This clearly distinguishes it from transcript tools like instagram_transcript and from platform-specific summarize siblings like tiktok_summarize or youtube_summarize.

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 communicates when to use this tool: when a concise AI summary of an Instagram Reel is needed 'without watching the video.' It also gives cost-related context that helps an agent decide, though it does not explicitly name alternatives such as instagram_transcript for verbatim text.

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