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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering safety. The description adds behavioral context beyond annotations: 'text-only, no widget rendered' and 'INTERNAL/preparatory tool' clarify that it produces no visible UI and is intended for backend chaining. No contradiction with annotations.

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 front-loaded with the most critical information ('INTERNAL/preparatory tool — text-only, no widget rendered') and then provides clear exclusionary and conditional guidance. Every sentence serves a distinct purpose and there is no wasted text, despite the length being justified by the need for sibling disambiguation.

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?

Given the empty input schema, rich annotations, and the presence of closely related siblings (list_reciters, play_ayahs), the description is fully complete. It covers use cases, exclusions, alternatives, and chaining behavior, leaving no ambiguity about when and how to invoke this tool.

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 input schema has zero parameters, so there are no parameter descriptions to provide. The rubric assigns a baseline of 4 for 0-parameter tools; the description reinforces the purpose by mentioning resolving reciter_id, which is the implicit output.

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 title 'Browse Quran reciters (data only)' and description clearly identify this as a text-only, internal/preparatory data lookup tool, distinct from the user-facing list_reciters. It specifies the verb 'lookup' and the resource 'reciters', and explicitly scopes it as non-widget, internal use.

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 explicit when-to-use and when-not-to-use guidance: NEVER use as user-facing answer, use list_reciters instead; use only for plain-text requests or when chaining into play_ayahs. It also provides a tie-breaker rule ('When in doubt, prefer list_reciters'), making tool selection unambiguous.

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