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

Annotations already declare a safe read (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description adds useful context beyond that: the ordering (newest first), the shape of each returned comment, and an auth prerequisite ('Needs the user's Cotlet API key with access to this app').

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?

The opening clause and the following sentence say the same thing twice ('newest first, with author, text, waveform timestamp and whether you replied' vs 'Each has the author, the text, the position on the waveform...and a flag for whether you already replied'). The filtering and auth notes are front-loaded well, but the duplicated payload description wastes space.

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, fully-documented 4-parameter list tool with no output schema, the description covers purpose, ordering, returned fields and auth needs, which is sufficient to call it correctly. Only the cursor-based pagination behavior is left unexplained.

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 semantic intent for two parameters ('since' = only what arrived after your last check, 'unanswered_only' = skip answered ones) beyond the schema's literal text. cursor and track_id are left entirely to the schema, so it is not a full 5.

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 ('Lists comments on your tracks') and enumerates the returned fields (author, text, waveform position, replied flag). It implicitly differs from siblings like soundcloud_reply_to_comment or soundcloud_delete_comment, but never names an alternative, so it stops short of explicit sibling differentiation.

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?

Gives parameter-level workflow hints ('Use since to read only what came in after your last check and unanswered_only to skip answered ones'), which implies a polling/inbox use case. However it never states when to prefer this tool over related siblings, so guidance is implied rather than explicit.

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