Update Scheduled Email

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

With no annotations, the description carries the full burden, and it does disclose the two eligibility guards that determine success. It omits what happens on violation (error vs. silent no-op), permission requirements, and whether the update is atomic or reversible, which matters for a mutation tool.

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 short sentences, action first then constraints, with no filler. Every clause carries information the agent would otherwise have to guess.

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 two-parameter mutation with no output schema, the description covers the essential preconditions and the single mutable field. The main remaining gap is failure behavior and permissions, but nothing critical to invoking it correctly is missing.

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%, and the schema already documents the em_xxx ID format, accepted time formats, and the 3-minute floor. The description only repeats the 3-minute constraint, adding no syntax or edge-case meaning beyond structured data.

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 ("Update a scheduled email's send time") and scopes it to the one mutable field, which cleanly separates it from cancel-email and send-email. It does not explicitly name those siblings, but the resource and action are unambiguous.

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 gives concrete eligibility conditions (status must be "scheduled", current send time at least 3 minutes out), which effectively says when this tool will work. It stops short of naming alternatives — e.g., cancel-email for scheduled mail or send-email for immediate delivery — so the agent must infer routing.

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