Start YouTube OAuth Flow

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

Annotations indicate readOnlyHint=false and idempotentHint=false, but the description adds valuable behavioral context: it specifies that the tool opens a local server and waits for a callback, which reveals implementation details and interactive behavior not covered by annotations. This helps the agent understand this is a blocking, interactive operation with side effects.

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 two concise sentences that efficiently convey the core action and key behavioral detail. Every word earns its place with no redundancy or fluff, making it easy to parse and front-loaded with essential information.

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?

Given the tool's complexity (OAuth flow initiation), annotations cover safety hints, but no output schema exists. The description provides enough context about the interactive nature (local server, callback waiting) to guide usage, though it could benefit from mentioning typical next steps or error handling. It's reasonably complete for a 0-parameter tool with behavioral annotations.

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?

With 0 parameters and 100% schema description coverage, the baseline is 4. The description doesn't need to explain parameters, and it doesn't add any parameter-specific information, which is appropriate given the empty 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 clearly states the tool's purpose: 'Start OAuth authentication flow' specifies the verb (start) and resource (OAuth flow). It distinguishes from siblings like youtube_checkAuth and youtube_getAuthUrl by focusing on initiating the flow rather than checking status or getting URLs. However, it doesn't explicitly differentiate from all authentication-related siblings.

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 implies usage context by mentioning 'Opens a local server and waits for callback,' suggesting this is for initiating authentication when no existing session exists. However, it doesn't explicitly state when to use this vs. alternatives like youtube_checkAuth (to verify existing auth) or youtube_getAuthUrl (to get URL without starting flow), nor does it mention prerequisites or exclusions.

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