instagram_highlight

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

Goes beyond the readOnlyHint/openWorldHint annotations by disclosing the credit cost (3 credits) and the 15-minute free-window caching behavior for the same account, plus the return content (signed CDN URLs). This is real operational context an agent needs before calling, though auth requirements are unspecified.

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?

Front-loads the purpose well, but the cost is stated twice ('Costs 3 credits the first time...' and a trailing 'Cost: 3 credits.'), making the last line redundant padding.

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 single-parameter read tool with no output schema, it covers return content, cost, and caching. The main gap is the undocumented id format, but the annotation-covered safety profile and stated outputs leave little else an agent must know.

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 0% and the description says nothing about the required 'id' parameter, not even the 'highlight:<id>' format shown only in the schema example. The phrase 'one highlight' hints at the resource but does not explain the parameter's syntax.

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?

States a specific verb (Get) and resource (items/photo and video inside one highlight), with useful scope detail (signed CDN URLs). The singular 'one highlight' implicitly distinguishes it from the listing sibling instagram_highlights, but the sibling is not named explicitly, so it falls short of a 5.

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?

No when-to-use or when-not-to-use guidance. Given the close sibling instagram_highlights (list highlights) the description never tells the agent which to pick, leaving the singular/plural distinction to be inferred from the name alone.

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