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

The description discloses overwrite semantics, UTF-8 encoding, a 512 KB cap, and the limitation against binary uploads. These go beyond the annotations and add meaningful behavioral context. The description agrees with the idempotentHint and destructiveHint annotations, so there is no contradiction.

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, focused sentences deliver purpose, behavior, and alternative guidance without any fluff. The most important information is front-loaded.

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 write operation with four documented parameters, no output schema, and no nested objects, the description covers the essential non-obvious details: overwrite behavior, encoding, size cap, and the binary-upload alternative. An agent has enough information to invoke 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 parameters are already well documented. The description adds useful value by clarifying that 'content' is written as UTF-8 and capped at 512 KB, which supplements the schema meaning rather than repeating it.

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?

The description clearly states a specific verb and resource: create or overwrite a text file over SFTP. It also naturally distinguishes itself from sftp_read and sftp_list by signaling the write direction, and from ssh_exec/scp by constraining scope to text files.

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?

The description explicitly tells the agent when to use an alternative: 'for binary uploads use a terminal/scp instead.' It also implies the right conditions for use by mentioning text files, UTF-8 content, and a 512 KB limit.

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