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

Annotations only declare readOnly and openWorld; the description adds material context they don't carry: the Instagram link is minted live from the official API with the account's own token and expires within hours, the TikTok link requires session cookies, and there's a hygiene constraint to use a temp folder and delete the file. That is exactly the extra behavioral detail annotations can't express.

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-loads the purpose, then segments Instagram vs TikTok behavior and the local-file hygiene rule into distinct sentences that each carry information. The deletion instruction is slightly lecturing but is a genuine operational constraint, so it earns its place.

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?

No output schema exists, and the description effectively covers return-value semantics by explaining what the URL is, how long it lives per platform, and what fetching it requires. Nothing needed to call it correctly is absent.

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?

Only one parameter (post_id) and schema description coverage is 100%, so the schema already explains it as the UUID 'id' from list_my_account_posts. The description adds no format, source, or constraint detail for post_id, so baseline 3 applies.

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 and resource ('Get a downloadable URL for the video'), and scopes it to the org's OWN posts (My Accounts), which implicitly separates it from get_post_download_url and get_asset_download_url siblings. An agent can pick it correctly 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?

Gives concrete when-to-use behavior per platform: on Instagram consume the URL immediately because it expires in hours; on TikTok the URL needs returned session cookies so external services generally can't fetch it. Missing an explicit 'use get_post_download_url for third-party posts instead' routing statement, which keeps it off a 5.

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