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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the overwrite risk is covered structurally. The description still adds real value beyond them: the 512 KB cap, the UTF-8 encoding requirement, and the fact that an existing file is overwritten rather than appended.

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?

Two compact sentences with zero filler; the core action leads and the size cap plus binary-upload fallback follow as constraints. Every clause 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?

For a mutation tool with no output schema, the description covers the key call-time facts: encoding, size limit, overwrite behavior, and the alternative for binary. It omits any note on required permissions or failure modes, which is a minor gap given the annotations already flag destructiveness.

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%, so host/path/content/username are already documented; the description only restates the UTF-8 nature of 'content'. It adds the 512 KB size ceiling, which is useful but not parameter syntax or format detail. Baseline 3 is appropriate.

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 (create or overwrite), resource (text file), and transport (SFTP on one of your servers). An agent can immediately separate this from sftp_read, sftp_list, and ssh_exec among the siblings.

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?

Explicitly routes binary uploads elsewhere ('for binary uploads use a terminal/scp instead'), which is a genuine when-not condition with a named alternative. It doesn't address other plausible confusions (e.g. vs. ssh_exec for writing files), so it stops short of full coverage.

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