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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world behavior, so safety is covered. The description adds real domain context (slash bass notes are handled; audio/lyrics/notation are out of scope), but says nothing about output format, enharmonic spelling behavior, or error handling for malformed chord strings.

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 short sentences: the capability is front-loaded and the scope boundary follows immediately. No filler, no restatement of the tool name.

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 three-parameter tool with no output schema and zero schema description coverage, the definition is under-specified: an agent cannot learn what preferFlats does or what format the chords string expects from either the schema or the description. The scope note is helpful but does not close the parameter 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 0% for all three parameters, so the description carries the full burden and does not meet it. It never explains the semitones direction/range or what preferFlats controls in the output, and 'chord symbols' is only loosely gestured at via the slash-bass mention.

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 (transpose) and resource (chord symbols), then narrows domain further with the slash-bass-note case. The explicit negative scope ('Does not process audio, lyrics, or notation files') lets an agent separate this from transcription/notation siblings 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?

Usage is implied by the domain exclusions, so an agent can infer this handles text chord symbols rather than audio or files. However, no sibling tool (spell_piano_chord, tab_to_piano_notes) is named as an alternative and no when-not condition is given beyond the input-format caveat.

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