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

Annotations only declare read-only, non-destructive, closed-world. The description goes well beyond that, disclosing ordering, the full status vocabulary, and the semantics of each state: uploaded items wait until `expires_at` before publishing, published items carry a `permalink`, failed items carry an `error`, expired items were deleted unpublished. That is genuine behavioral context an agent cannot get from structured fields.

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?

Front-loaded with the core fact (whose videos, what kind, what order), followed by a compact status glossary. Every clause carries information; nothing is redundant padding.

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 an output schema present, the description need not document return shapes — yet it usefully explains the status/note fields anyway. For a zero-parameter, read-only listing tool, an agent has everything needed to call it 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?

The tool takes zero parameters, so the baseline is 4; there is nothing for the description to clarify and it does not need to. It correctly avoids inventing filter syntax that the schema does not offer.

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 resource scope (the user's Instagram videos), an ordering guarantee (newest first), and defines the resource further by enumerating the lifecycle states a video can be in. An agent can distinguish this from list_images and list_instagram_posts without opening any 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 is implied — call it to enumerate the user's videos and see where each stands — but there is no explicit when-to-use framing, no stated precondition (e.g., after start_video_upload or before publish_instagram_video), and no pointer to alternatives such as list_instagram_posts. Minimum viable, with a clear gap.

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