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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the partial-update contract ('Only provided fields change') and mapping to PATCH /api/v1/media/{media}, though it says nothing about permissions or what the response contains.

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, zero filler. The subject (what gets updated) is front-loaded and the partial-update qualifier and API mapping follow immediately.

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 low-risk partial-update tool with full schema coverage and no output schema, the description covers purpose, mutability semantics, and API parity. Return behavior and authorization requirements are the only meaningful gaps, and both are minor for a PATCH-style field updater.

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%, so every parameter already carries its own description, max length, and null-clears semantics. The description lists the same field names without adding format, validation, or clearing rules beyond the schema, so the baseline 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?

States a specific verb ('Update') and resource ('a media file's metadata') and enumerates the affected fields (name plus audio tags title/artist/album/year/genre). The resource scoping clearly separates it from siblings like update_folder, update_stream, and update_tag.

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 gives clear partial-update context ('Only provided fields change') and the PATCH endpoint it mirrors, which implies usage for incremental edits. However it never states when to prefer this over siblings such as update_tag or update_stream, leaving alternative selection to inference.

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