zas_send_direct_fallback

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

With no annotations, the description carries the full behavioral burden and does so well: it explains encryption on the local machine, storage of only the encrypted copy in Cloudflare R2 for up to 24 hours, no use of owner space, later download by the claiming device, and that bytes pass through storage rather than remaining purely Directo. It also discloses the consent requirement and that the owner sees the agent mark and agent name on every device.

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 purpose is front-loaded and most sentences earn their place by clarifying the fallback behavior, consent requirement, parameter, and owner visibility. It is fairly long and somewhat jargon-heavy around "Directo", but the length is justified for a fallback operation with no annotations.

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 no-annotation fallback send tool with no output schema, the description covers the critical context: when it applies, what happens to the file, retention, privacy implications, consent, and parameter source. An agent has enough information to decide whether to use it and how 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?

There is only one required parameter and schema description coverage is 100%, so the schema already explains that job is the failed Directo send id reported by zas_send_direct or zas_jobs. The description adds "Pass the failed job's id" but no further syntax or format detail beyond the schema, so the baseline of 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?

The description states a specific verb and resource: deliver the same file after a zas_send_direct job failed in flight. It explicitly distinguishes this fallback path from the original direct send, so an agent can tell exactly what the tool is for without opening the 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?

The trigger condition is explicit: use this only after a zas_send_direct job failed in flight and pass that failed job's id. It also adds a clear prerequisite to ask the owner first, though it does not explicitly say not to use this for brand-new sends where zas_send_direct or zas_send_file should be chosen.

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