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

Annotations already supply readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the safety profile is covered; the description goes further by disclosing the specific 402 error for X, the returned authUrl that must be opened by the account owner, and the terminal states to poll for. It stops short of idempotency, rate limits, or permission requirements.

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?

One dense paragraph that is front-loaded with the action and platform list, then layers platform-specific caveats and the lifecycle hand-off. Every sentence carries information, though the Instagram authMethod sentence is a little convoluted and the platform enumeration could be tightened.

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?

With no output schema, the description correctly fills the gap by naming the returned authUrl and the follow-up polling contract. The main gap is the enum/description platform mismatch and the undocumented redirectUrl, which leave a little room for an agent to mis-invoke on less common providers.

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 only 25% (only profileId is described), so the description must compensate. It does explain authMethod's two modes, but redirectUrl is never mentioned, and the platform list in the prose ('Instagram, Facebook, TikTok, YouTube or X') omits whatsapp and google_business_profile from the schema enum, leaving ambiguity rather than clarifying every parameter.

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?

Opens with a specific verb+resource ('Start connecting an ... account') and enumerates the supported platforms, so it is immediately distinguishable from siblings like disconnect_account, refresh_accounts, and get_connect_session. The async hand-off to get_connect_session is stated explicitly, making the tool's role in the lifecycle unambiguous.

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?

Gives real when-to-use context: X returns 402 unless enabled, and Instagram callers must choose between instagram_login and facebook_login. It also routes the agent forward ('then poll get_connect_session until the status is connected, failed or expired'), which is actionable sequencing guidance, though it never states a true alternative or exclusion for the start step itself.

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