send_to_stream

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

Annotations already mark this as openWorldHint and destructiveHint, and the description adds meaningful behavioral context: it sends immediately, reaches every subscriber, enforces a per-request cap of 1000, and reports excess recipients as skipped. This goes beyond the structured annotations without contradicting them.

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?

The description is only two sentences, front-loads the core action, and every clause earns its place: the immediate broadcast behavior, the input alternatives, the cap, and the campaign routing guidance. There is no filler or redundancy.

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 7-parameter destructive tool with no output schema, this description covers the key operational facts: immediacy, recipient scope, input modes, the cap, and the fallback for larger audiences. It does not spell out every edge case, but the schema covers parameter syntax and the annotations cover the safety profile.

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%, so the baseline is 3, but the description adds genuine semantic value by framing the valid combinations (subject/body versus template) and by flagging the 1000-recipient cap that affects how the request should be constructed. It does not need to re-describe each parameter since the schema already does.

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 ('sends mail immediately') and resource ('every subscriber of a broadcast stream'), which clearly distinguishes this from single-recipient siblings like send_email/send_email_with_template and from scheduled campaigns. It also clarifies the immediate-send nature of the operation.

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 gives explicit instructions on acceptable input modes ('either a subject with a body, or a template permalink') and explicitly routes larger audiences to a campaign instead. It does not explicitly name sibling alternatives, but the campaign reference and per-request cap give usable selection guidance.

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