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

Annotations only cover the safety profile (readOnly, idempotent, openWorld, non-destructive). The description adds substantially beyond that: size thresholds (~1 MB image, 256 KB text), what is returned for unhandled types (type/size/name/download url), the requirement to reuse the Authorization header when GETting the url, and the ~10 s PDF conversion that re-runs on each fetch.

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?

Front-loaded with the operation and organized by return branch, part, then format, ending with the raw endpoint. Dense but essentially waste-free; readability suffers slightly from packing many clauses into a single long sentence.

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 return-value burden and does so fully — it explains the three possible response shapes, the download-url path and its auth requirement, and conversion timing. Nothing material for correct invocation is missing.

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%, so the baseline is 3, but the description adds meaning beyond the schema: format=pdf is described as a server-side conversion taking about 10 seconds whose download url re-converts when fetched, and part=cover is tied to the podcast cover flow.

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 ('Fetch an asset by assetId') and then details the three distinct return paths by asset type and size. An agent can distinguish this from list-style siblings like muse_list_assets or muse_read_file without opening any 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?

The description establishes clear context: this is the by-id retrieval tool, with part=cover scoped to podcast assets and format=pdf scoped to document assets. It does not explicitly name alternatives (e.g. use muse_list_assets to discover assetIds), so it stops short of full when/when-not routing.

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