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

With no annotations, the description carries the full burden and does well: 'each returned once' discloses the consumption/at-most-once semantics, and it names the returned fields (saved state, thread ID) despite there being no output schema. It omits auth/rate-limit or failure behavior, so not 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?

Two tight sentences, front-loaded with the core action; no filler. The final sentence could have been folded in and the bracketed '[agent-wake]' prefix spends tokens on a namespace marker, keeping it below 5.

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 single-optional-param, no-output-schema read tool, the description covers purpose, trigger timing, and return shape (state + thread ID), which is enough to call it correctly. Details like what happens to consumed wake-ups on subsequent calls or how to resume from 'state' are left implicit.

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 already fully documents 'inbox' including the 12+ char and API-key fallback rules. The description only restates 'your inbox' and adds no syntax or format detail, 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+resource ('collect wake-ups... and list upcoming ones') scoped to 'your inbox,' and the paired name makes clear it is the read counterpart to wake_schedule_wake and wake_cancel_wake. An agent can distinguish check vs schedule vs cancel without opening any 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?

'Call this at the start of a session' gives an explicit triggering condition, which is stronger than most definitions. It stops short of naming alternatives or when-not to use it (e.g., relation to wake_schedule_wake), so it does not reach a 5.

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