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

Annotations already establish that this is a safe, idempotent, closed-world read, so the description focuses on behavior that structured fields cannot express: it explicitly disclaims measuring, scoring, inferring current state, drawing clinical conclusions, or explaining a specific song. It also discloses the degraded-path behavior (returns one short question when the goal is unclear) and what the output includes (public sources plus the limits of the evidence).

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 trigger condition is front-loaded in the first clause, followed by the goal list, the mapping behavior, and the disclaimers in a logical order. It is dense but nearly every clause carries information; the 'Guidance only:' clause runs slightly long with four enumerated negatives, though each rules out a plausible misuse.

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, yet the description fully characterizes the return: one of four states, bounded guidance, public sources, evidence limits, or a single clarifying question. For a two-parameter read-only tool that is everything an agent needs to invoke it and interpret the result.

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% and the schema already spells out that 'goal' is the person's own words rather than a mood or song, and that 'service' is apple_music/spotify/unknown. The description's framing largely restates that instead of adding new meaning. Baseline 3 applies because the schema carries the parameter burden.

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 names a specific verb and resource: it maps a stated listening goal onto one of four named CHRP states (Flow, Ready, Recharge, Recover) and returns bounded guidance. The states are enumerated explicitly, so an agent can distinguish this from sibling lookups like get_states or get_science without opening a 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?

It opens with a clear triggering condition ('Use when someone says what they need their music to help them do next') and enumerates concrete goal categories (focus, game prep, workout, reset, recovery). It also states exclusions ('Not for trivia, playlist generation, or entertainment-only requests') and the unclear-goal fallback. It stops short of naming which sibling to call instead for the excluded cases, so the routing is implied rather than explicit.

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