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

With no annotations, the description carries the full behavioral burden, and it does disclose several traits: determinism ('Same day → same answer'), a constraint against inventing pillars/fortune claims, non-diagnostic scope ('Not a diagnosis'), and no auth requirement ('no API key'). These are genuinely useful disclosures, though the compressed form leaves some boundaries ('Adjust ≠ infuse energy', 'Preview ≠ prediction') ambiguous.

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 and determinism claims are front-loaded, which is good, but the body is a string of telegraphic fragments that drift into cryptic slogans ('Adjust ≠ infuse energy', 'Preview ≠ prediction') whose meaning an agent cannot reliably recover. Compact but not every sentence clearly earns its place.

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?

There is no output schema and no annotations, so the description should ideally describe the shape of the returned rhythm guidance, and it does not. It covers scope, determinism, and safety limits adequately, but a first-time caller still does not know what the answer will look like.

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%, so the schema already documents date, hour, and locale semantics fully, including the default timezone and 时支 format. The description adds no parameter-level guidance beyond what the schema provides, making the baseline 3 appropriate.

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 establishes that this is a deterministic body-energy lookup derived from 'solar term + hour + month posture × sky tightness', which is a specific computation. However, the framing verb is vague ('looks up a deterministic rules engine') and 'body-energy rehearsal' is jargon; it never distinguishes itself from likely-overlapping siblings such as energy_adjust, today_rhythm, or sky_window.

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?

It gives concrete trigger phrasings (今晚要不要提前睡 / 今天该不该加练 / 现在这个时辰适不适合动 / train or rest), which clearly tell an agent when to reach for this tool. It stops short of naming a when-not condition or pointing to a sibling alternative, so it falls just below the top band.

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