get_user_latest_post_time

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

No annotations are provided, so the description carries the full burden. It usefully discloses that the value is UTC, where account credentials live (~/.facebook-mcp/accounts/<account>/), and that the account defaults to the configured one, but it says nothing about auth failures, private/nonexistent users, or rate limits.

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?

Three compact sentences, front-loaded with the resource and return value before the input-format and account caveats. No filler.

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?

An output schema exists, so return-value details need not be repeated, and both parameters are covered. The only gap is behavior on failure cases (unknown user, private profile), which is minor for a simple read-only lookup.

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 description coverage is 0%, so the description must carry the parameter meaning, and it does: it specifies the username format (no URL, no leading '@') with an example, and explains that account selects the credential set under ~/.facebook-mcp/accounts/<account>/ and defaults to the configured account.

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: the publish time (UTC) of a user's latest post, keyed by username. The 'latest post' scoping implicitly distinguishes it from the sibling get_user_recent_posts.

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 only implied by the 'latest post' phrasing; there is no explicit statement of when to pick this over get_user_recent_posts or any other sibling. It does give input-format guidance (username, account), but that is parameter help rather than when/when-not guidance.

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