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

Annotations declare mutation semantics (readOnlyHint=false, destructiveHint=true, idempotentHint=true), and the description adds context those annotations cannot convey: the existing callback URL is replaced outright and the change applies to all of the account's streams going forward. That replacement/scope behavior is exactly the kind of state-change disclosure an agent needs, though no auth or permission requirements are mentioned.

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 sentences, front-loaded with the gating condition and then the state-change semantics, with no redundant restatement of the name or title. Every clause carries information an agent needs at call time.

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 explained, and the destructive/idempotent annotations plus the description's replacement semantics cover the mutation risk profile. The only gap is the absence of any authentication or permission prerequisite for changing an account-wide setting.

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% and the single parameter is already documented as 'Public http(s) URL that will receive the results', so the schema carries the burden. The description adds marginal value by noting the URL also receives stream notifications, but contributes no format or validation detail beyond the schema.

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 gives a specific verb (set/change) and resource (the account's stream recognition-results callback URL), so an agent knows exactly what is being configured. It also clarifies scope (account-wide, replacing the current URL) which distinguishes it from a per-stream update or the getter sibling, though it never names get_stream_callback_url explicitly.

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?

'Use this only when the user asks to set or change the URL...' provides an explicit gating condition and an implied exclusion for other cases. It stops short of naming the alternative tool (get_stream_callback_url) or stating when not to use it beyond 'only when the user asks'.

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