Set a subuser's file blocklist

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

With no annotations, the description carries the full load and delivers real behavior: addon prerequisite, wings-side matching semantics, negation anchoring to server root, and root-admin bypass. It stops short of stating that the deny list is replaced wholesale on each call and says nothing about auth scope, which is the main remaining gap.

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?

The routing constraint and addon prerequisite come first, then syntax rules with concrete examples, then the root-admin caveat. Each sentence covers a distinct fact and none repeats schema or title content.

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 an 8-parameter mutation tool with no annotations and no output schema, the description supplies the routing, prerequisite, and matching semantics an agent needs to call it correctly. The replacement-vs-merge behavior of denyfiles is only implied via the schema's 'empty array to clear' note.

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 already 88%, so the baseline is 3; the description earns above that by documenting pattern syntax the schema never explains — gitignore semantics, depth-agnostic matching, trailing-slash directory rules, and '!' re-allow with full-path anchoring. denyfiles and hidefiles semantics remain schema-only.

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 concrete verb and resource ('Set which files and directories a subuser may not touch') plus the enabling condition (sftp-permissions addon). It also explicitly distinguishes itself from subuser_update, so an agent can route correctly without inspecting schemas.

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?

'This is a route of its own: the fields are read back by subuser_list but sending them to subuser_update does nothing' names both the alternative and the failure mode of picking wrong. The addon prerequisite further constrains when the tool is applicable.

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