send_story

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

Annotations cover openWorld and non-idempotency, but the description adds substantially more: the 20-sends-per-minute rate limit, that the story is not saved to the local store, that files must lie within allowed send roots and not be hidden, and the exact return shape. These are behavioral traits beyond the structured fields.

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?

Purpose, alternatives and the path constraint are front-loaded, and the sentence flow mirrors call order. It is dense and slightly packed, but each clause (rate limit, local-store, non-idempotency, return value) earns its place.

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?

No output schema exists, yet the description supplies the return value ({status: 'posted', timestamp}), the visibility window, failure conditions (hidden file / outside roots) and rate-limit context. Nothing an agent needs to invoke it correctly 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 coverage is 100% (baseline 3), and the description still adds meaning beyond it: path is constrained to one local image/video inside allowed folders (with the env override), group_id must come from list_groups, and allow_replies=false disables replies. Adds real value over the terse schema descriptions.

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+resource ('Post an image or video as a Signal story') with scope (24-hour visibility) and immediately names the sibling tools it is not (send_message / send_attachment) for direct messaging. An agent can route between these without opening a schema.

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 names alternatives ('Use send_message / send_attachment to message someone directly') and the condition selecting the group variant ('group_id (from list_groups) posts to that group's story instead of My Story'). When-to-use and when-not logic is fully specified.

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