instagram_stories

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: anonymous viewing, the 24-hour content window, signed CDN links that expire after a few hours, and a 3-credit cost. It stops short of describing pagination or error/auth behavior for private accounts.

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 compact, front-loaded sentences with no filler: purpose first, then content/expiry details, then cost. Well structured, though the cost line could arguably sit with other metadata.

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?

With a simple two-parameter schema, no required params, and no output schema, the description covers everything an agent needs: what is fetched, from whom (public accounts), what comes back (image/video URLs), that links expire, and the cost. Nothing material is missing.

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 both parameters (user_id, username) are well documented in the schema itself, including the 'pass this or...' either/or relationship. The description adds nothing about the parameters, so the baseline of 3 is appropriate.

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?

Specific verb+resource ('View Instagram stories') with a defined scope (last 24 hours, public accounts). It clearly describes what is returned (image and video URLs), but it does not explicitly distinguish itself from closely related siblings like instagram_highlights or instagram_highlight, which also surface story content.

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?

Implicit usage is conveyed via the constraints ('last 24 hours', 'public account'), so an agent can infer when the tool applies. However, there is no explicit when-to-use vs alternatives guidance — nothing tells the agent to use instagram_highlights for older/persistent stories, which is the main ambiguity given the sibling list.

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