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

Genuinely adds behavior beyond the annotations: partial-update semantics ('Omitted fields retain current values') and a destructive side effect not implied by destructiveHint alone — a supplied description flattens existing formatting to plain text. It does not discuss permission/auth requirements or failure behavior, so it falls short of a full behavioral picture for a destructive write.

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?

Four short sentences, front-loaded with the operation and its semantics, then the exclusions. Every sentence carries distinct information; none is 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?

An output schema exists, so return values need not be described, and the annotations already declare the safety profile. Combined with ownership scope, omit-to-keep semantics, and explicit exclusions, an agent has everything needed to invoke this correctly.

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%, so the per-parameter baseline is 3. The description adds cross-cutting meaning the schema only repeats per field (omit-to-keep), and the formatting-loss behavior for the description parameter is parameter-relevant context the schema does not convey.

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 and resource ('Update owned stream metadata') and immediately bounds the scope by naming what it does not touch (visibility, pricing, custom-target configuration), which separates it from siblings like set_stream_custom_targets and patch_stream_custom_targets. An agent can identify the tool without opening the 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?

Usage context is clear: it applies to streams the caller owns (reinforced by the 'from streams_created' hint) and it explicitly excludes visibility, pricing, and custom-target changes, implicitly routing those to the sibling tools. It stops short of naming an alternative tool outright, so it is clear context rather than explicit routing.

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