seek_relative

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

With no annotations provided, the description carries the full behavioral burden. It discloses that the operation performs one read and one write, names the exact endpoints, and notes that the result is clamped to [0, duration]. This makes the mutating side effect and boundary behavior explicit, though it does not address error cases like no active playback.

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 description is a single, tightly-packed line that front-loads the core meaning, then efficiently adds endpoint details and the clamp behavior. The 🟢 marker and '(1 read + 1 write)' note are compact and informative rather than filler.

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 4-parameter tool with no output schema, the description is largely complete: it gives the operation, the API sequence, the side effect, and the clamping behavior. The main gap is that it does not mention the prerequisite of active playback or how device_id affects the call, but the schema covers the parameter's meaning.

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?

The schema already documents all four parameters at 100% coverage, so the baseline is 3. The description adds extra value by clarifying that delta_ms is interpreted relative to current progress and that the effective range is clamped to the current track duration, which is not stated in the schema.

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 the operation explicitly ('Relative seek') and distinguishes it from any absolute seek sibling by saying the movement is 'forward/back by delta_ms from current progress'. It also states the underlying API calls (GET /me/player then PUT /me/player/seek), making the tool's function unambiguous.

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 phrase 'Relative seek' and 'from current progress' clearly communicate when to use this tool: when an offset from the current playback position is needed. It does not explicitly name sibling alternatives such as 'seek' for absolute positioning, so it stops short of full exclusion guidance, but the context is clear.

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