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

Annotations already declare a non-read-only, non-idempotent, destructive write, so the bar is lower. The description usefully adds a latency expectation ('Takes up to a minute') and hints that it returns sessions, but it never explains WHY it is destructive — that it presumably overwrites/regenerates today's existing sessions. That omission matters most for an agent deciding whether to call it repeatedly.

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 sentences with no padding, and the outcome is front-loaded. The phrasing is slightly tangled ('tells the coach... and the coach designs'), but nothing is wasted.

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?

With no output schema, the description should describe the return value, and 'Returns them' is vague about what exactly comes back and in what form. It also leaves the destructive overwrite behavior unexplained. Adequate but with clear gaps for a write tool with a non-trivial return payload.

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%, so the schema fully documents today, minutes, and cannot_do (including the 05:00 date rule and the enum values). The description adds no parameter meaning beyond that, 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 conveys the outcome (input today's available minutes and constraints, coach designs today's sessions), which is a recognizable resource. However, the actor framing is muddled — 'tells the coach' reads as if the tool speaks to the coach rather than the user informing the coach — and it never distinguishes itself from close siblings like check_readiness, today, or ask_coach. Purpose is inferable but not crisp.

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?

There is no explicit when-to-use statement and no alternatives named. Given siblings check_readiness, today, and ask_coach all touch today's readiness/planning, the description should route the agent among them; it does not. Only the phrase 'the morning check-in' implies a daily trigger, which is weak guidance.

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