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

Annotations already cover read-only, idempotent, non-destructive, open-world. The description adds non-obvious live behavior: it reads from the platform in real time, so an empty result can indicate connectivity failure rather than absence of destinations. That is genuine value beyond structured fields, though timeout/retry behavior and pagination are not addressed.

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 core purpose, with the actionable follow-up (use ids in schedule_post) and the failure caveat at the end. The long platform enumeration is somewhat listy but it maps directly to the enum and earns its space.

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 and a live-source tool, the description does the work of explaining what comes back (ids for platform_meta) and when an empty result is ambiguous. It omits the exact response shape and pagination, but for a lookup feeding schedule_post the essentials are present.

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 all three parameters are documented in-schema, so the baseline is 3. The description hints that the value kind must correspond to the account's platform (matching the schema note) but adds no syntax or format detail beyond what the schema already provides.

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 ('look up') and resource ('destinations a connected account can publish into'), then enumerates the exact platforms covered by the kind enum. An agent can distinguish this from siblings like list_connections or schedule_post 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?

Describes the downstream use case explicitly — 'Use the returned ids in schedule_post's platform_meta' — which tells the agent when this tool is needed. It does not state prerequisites (e.g., the account must exist and be connected) or when-not to use it, so it stops short of full routing guidance.

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