zas_send_file

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

With no annotations, the description carries the burden well: it discloses the return contract (item id, or a job id when the upload exceeds a minute), the refusal behavior in Directo mode, and the visibility side effect (owner sees every item with the >_ agent mark and agent name on every device). It omits permission/size limits and any rate-limit or failure behavior, keeping it short of a 5.

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?

Four sentences, front-loaded with the action, then return contract, then the routing exception, then the safety and visibility notes. Every sentence carries distinct information with no repetition of the schema or title.

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?

No output schema exists, but the description explains the two possible return values, the async case, and the visibility side effect, which is what an agent needs to act on the result. Remaining gaps are secondary: file size limits, permission requirements on the target channel, and how the job id is later resolved (presumably via zas_jobs).

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 each of the four parameters is already documented in the schema, including the clamping behavior of expires_in_days. The description adds only a light constraint on path ("any file this process can read"), which is capability context rather than parameter syntax, so the baseline 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 ("Send a file from this machine into one of the owner's Zas channels") and explicitly carves out the case where it does not apply ("A channel in Directo mode refuses this tool: use zas_send_direct there"). An agent can distinguish it from the direct-send siblings without opening either 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 a concrete when-not condition (Directo-mode channels) plus the named alternative, and adds a safety precondition ("confirm with the owner before sending secrets, keys or credentials"). It does not distinguish itself from other siblings like zas_replace_file or zas_send_note, so routing guidance is clear but not exhaustive.

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