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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, so safety and determinism are covered. The description adds real context beyond that: the return payload shape (frets, fingering 'where known', note spellings, text diagram) and the fact that fingering may be missing, which sets expectations for a partial response.

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?

One dense sentence, front-loaded with the verb and resource, with the chord-type list placed at the end as supporting detail. The enumeration is long but each entry reduces the chance of an unsupported-chord call, so it earns most of its space.

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 carries the burden of describing the return value, and it does so concretely (shapes, frets, fingering where known, notes, text diagram). For a single-parameter read-only lookup, an agent has everything needed to call 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 coverage is 100% and the single parameter is well exemplified, so the baseline is 3. The description earns a point by enumerating the accepted chord vocabulary (maj7, m7b5, dim7, sus, add9, power chords, slash chords like G/B), which tells the agent what syntax will actually resolve beyond the handful of schema examples.

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 ('Returns playable guitar shapes for a chord name') and immediately scopes what comes back: open and barre shapes, frets, fingering, notes, diagram. This clearly distinguishes it from the inverse-direction sibling identify_chord, which takes shapes and returns a name.

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?

Usage is only implied by the input ('for a chord name'), and there is no explicit routing guidance toward identify_chord, get_scale, or transpose_chords. An agent can infer when to call it, but nothing states when not to or which sibling to prefer.

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