get_v2_user_stories_by_username

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so safety is covered. The description adds real behavioral context beyond them: it is a live Instagram request, slower than the id-based variant, and billed at 3 requests per call vs 2. It does not describe the story payload shape, but that is a minor gap for a read 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 tight sentences plus an endpoint annotation. The core purpose and the differentiating usage caveat are front-loaded, with no filler.

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 read-only, no-output-schema tool, the description covers purpose, selection criteria, cost, and liveness, which is most of what an agent needs. Return-format detail is absent but not essential given it is a plain read endpoint.

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 coverage is 67% - force and safe_int carry their own descriptions, and username is self-evident. The description adds no parameter-level meaning (e.g. what force skips, or how safe_int affects output), so it does not exceed the schema's own documentation.

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) plus resource (an Instagram user's active stories) and the scoping key (by username). It explicitly distinguishes itself from the sibling get_v2_user_stories, so an agent can separate the two without opening schemas.

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?

Gives an explicit when-to-use condition ('only when you have a handle and not the user id') and names the alternative (get_v2_user_stories) along with the trade-off (slower, higher billing). The routing decision is fully specified.

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