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

Annotations already declare destructive=true and readOnly=false, but the description adds substantial context: a temporary read-only SSH key, no data through AskYourStack, rsync required on both servers, source port reachability, background execution returning a job_id, a 24-hour open link, and the approval requirement for mirror deletes. This exceeds the annotation bar considerably, though it omits failure/timeout 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?

Front-loaded with the core action and mechanism, and every clause is informative rather than filler. It is delivered as one dense paragraph, which slightly hurts scannability but keeps the definition compact.

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, the description still explains the return (a job_id), how to follow the job (job_output on the target), the lifecycle end (transfer_close), and prerequisites. For an 8-parameter migration tool this leaves an agent with what it needs 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?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema: mirror's destructive deletion and approval requirement, and concrete excludes examples (var/cache, var/page_cache, generated) that guide correct use.

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+resource ('Copy a folder from one of the user's servers to another, directly between them, for migrations') and names its mechanism (rsync over SSH). It clearly distinguishes itself from siblings like transfer_close and job_output, which it explicitly routes to.

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 explicit when-to-use (migrations), a repeat-use pattern (call again with the same arguments for a catch-up copy), and names the companion tools (job_output to follow the job, transfer_close when done). It also flags when mirror deletes files and that this needs approval.

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