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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond the annotations: the response contains notes, formula, fingering, free diagram image URLs and a listening link. It omits any error behavior for invalid symbols, so it is 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?

A single sentence that front-loads the concrete outputs and then the extras (image URLs, listen link). It is dense but every clause earns its place; a slightly cleaner split of primary payload vs. extras would be ideal.

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 read-only, single-parameter lookup with no output schema, the description does the necessary work by describing what comes back, including media URLs that an agent would not otherwise anticipate. It still does not explain behavior on an invalid or unknown chord, leaving a minor gap.

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 single chord parameter is documented with the same example symbols quoted in the description, so the schema already carries the semantics. The description adds no new syntax or format rules, 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 names a specific resource (a chord symbol) and enumerates the payload: notes, formula, guitar fingering, diagram image URLs and an audio link. An agent can distinguish it from scale_info and transpose_chords. The action verb is only implied (it reads as a noun phrase rather than 'returns X for Y'), which keeps it short of a 5.

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 when-to-use or when-not-to-use guidance and no routing to alternatives such as scale_info for scales or transpose_chords for changing key. Usage is only implied by the resource being a chord. Nothing tells the agent what to do for an unrecognized chord symbol.

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