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

Annotations already declare readOnly/idempotent/non-destructive, so the description adds real value instead by disclosing the Premier-plan gating on the stem type and the underlying POST /music/download endpoint. It omits link expiry or rate-limit behavior, which keeps it short of 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?

Two sentences, zero waste: the primary action and its plan constraint come first, the sibling routing second. Nothing is padding.

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?

Covers purpose, plan gating, and sibling routing for a two-enum read tool. With no output schema present, it does not describe what the returned link looks like or whether it expires, which is a minor but real gap for a download tool.

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 both parameters are fully documented there, including the enum meanings and the song_id format, so the baseline is 3. The description's restatement of the two type values adds little beyond what the schema already spells out.

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 (get a download link) and resource (basic stems package or license certificate) plus the enum values that select between them. It explicitly distinguishes itself from the sibling pair mureka_extract_stems/mureka_download_stems, so an agent can route without opening schemas.

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?

Explicitly names the alternative path ('For the full split into up to 12 stems with MIDI and DAW sessions use mureka_extract_stems, then mureka_download_stems') and states the prerequisite for the stem type (Mureka's Premier plan). Both the when-to-use and when-to-use-something-else conditions are given.

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