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

Beyond the annotations (readOnlyHint, destructiveHint), the description discloses that this tool renders an interactive widget, is meant to be the final tool call for a request, and should not be followed by lookup_tafsirs. This added context about output modality and tool orchestration is valuable and contradicts nothing in the 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 longer than a minimal two-sentence blurb but every sentence carries operational value: default role, usage examples, finality rule, widget behavior, and alternative conditions. It is front-loaded with 'DEFAULT tool' and structured as a priority order, making it easy for the agent to parse. Slightly verbose but not padded.

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 a simple single-parameter schema, existing output schema, and annotations already covering the read-only/destructive nature, the description fully covers the operational context: when to call, what it displays, how it relates to sibling tools, and when to prefer the alternative. No significant gaps remain.

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 describes the 'languages' parameter with an example, so schema coverage is 100%. The description does not add parameter-level detail beyond the schema, which is fine per the baseline rule. The examples in the description ('list English tafsirs') tangentially imply language filtering but do not enhance the schema's meaning.

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 clearly states the tool's purpose: it is the default for user-facing tafsir-listing questions, showing the catalog in an interactive widget. It uses specific verbs ('list', 'browse', 'shows') and explicitly distinguishes itself from the sibling lookup_tafsirs by framing itself as the widget-based display tool.

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?

It provides explicit when-to-use guidance with concrete query examples ('what tafsirs are supported', 'list English tafsirs'), and when-not-to-use conditions: only use lookup_tafsirs when the user wants plain text/raw data or when piping into ayah_tafsir without showing the list. Ends with 'When in doubt, use this widget', giving a clear decision rule.

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