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

Annotations already flag destructiveHint=true and readOnlyHint=false, but the description adds real consequence detail the annotations cannot convey: FTP login breaks until a new password is set and the old password is unrecoverable. The confirm gate and the 'fails when no password is set' condition live in the schema rather than the description, so it is not fully self-contained on behavior.

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 short sentences with the consequence front-loaded, which is the right order. The final sentence about apps_delete is garbled ('with apps_delete ftp_delete instead'), costing clarity in what should be a crisp disambiguation.

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?

For a two-parameter destructive tool with full schema coverage and no output schema, the description covers irreversibility, the resulting broken-login state and the sibling to use for a different deletion. The only gap is the imprecise cross-reference sentence and no mention of how to restore service beyond naming ftp_write.

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 100% and the enum documents the single action plus its required confirm parameter in detail. The description adds no parameter-level syntax or format information beyond what the schema already provides, so the baseline of 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 (remove the FTP password of the active site) and immediately delimits scope against two siblings: ftp_write to set a new password and apps_delete for deleting an FTP account. An agent can distinguish this from every other ftp_* and *_delete tool 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 clear when-to-use context (only for the password of the active site) and names the alternative path for a related-but-different operation (deleting an FTP account via apps_delete). No explicit exclusions such as prerequisites for the 'active site' selection, and the final cross-reference sentence is grammatically mangled, which slightly blunts the routing guidance.

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