is_valid_spotify_uri

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

With no annotations provided, the description carries the full burden and does well: 'evaluated locally' discloses that no API call is made, and 'true only for well-formed spotify: URIs with a 22-char base62 ID' precisely defines the acceptance criteria. It does not explicitly state whether invalid input returns false versus throwing, but the 'true only for' phrasing strongly implies a pure boolean result.

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?

A single well-structured sentence with zero fluff. Every component earns its place: return type (boolean), scope (single), validity criteria (spotify: URI, 22-char base62), and behavior (evaluated locally). The most decision-relevant information is front-loaded.

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 simple 1-parameter pure validation function with no output schema, the description covers purpose, return type, acceptance criteria, and local evaluation. The only minor gap is the lack of explicit statements about edge-case handling (e.g., whether non-URI strings yield false or an error), but given the tool's simplicity, nothing critical 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% and the schema already describes the parameter as 'Spotify reference to check', so the baseline is 3. The description adds meaningful value by clarifying the expected format — spotify: URIs with 22-char base62 IDs — which disambiguates the parameter beyond the schema's generic wording.

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 states a specific verb ('Boolean validity check'), a precise resource ('single Spotify reference'), and exact validity criteria ('well-formed spotify: URIs with a 22-char base62 ID'). However, it does not name or differentiate from direct sibling tools like validate_spotify_uri, parse_spotify_uri, or classify_spotify_uris, so an agent must infer the distinction from the word 'Boolean' alone.

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 implies when to use the tool (when a boolean, locally-evaluated validity answer is needed) and hints at scope ('single'), but it provides no explicit when-not-to-use guidance or alternatives such as 'use validate_spotify_uri for detailed validation errors'. The usage context is inferable but never stated.

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