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

The description is consistent with the annotations (readOnlyHint and idempotentHint both indicate a safe lookup operation). It adds that the tool fetches a hadith from Sahih al-Bukhari, which gives source specificity. However, it does not disclose any further behavioral details such as what happens if the book doesn't exist, how results are returned, or whether the hadith is randomly selected.

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, direct sentence that front-loads the main purpose and includes the optional parameter behavior. No wasted words or redundancy.

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 lookup tool with only one optional parameter and no output schema, the description is mostly sufficient. However, it does not explicitly state what the return value is (e.g., the hadith text or reference), and the misleading title adds context confusion. A more complete description would mention the output format and clarify that it is a hadith lookup, not prayer times.

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 description covers 100% of the parameter (`book` is described as 'Book number within Sahih al-Bukhari. Omit for a saying from any book'). The description adds minimal extra parameter semantics beyond repeating the schema, so the baseline of 3 is appropriate.

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 function: 'Look up a hadith from Sahih al-Bukhari, optionally from a given book.' This specifies a verb and resource. However, the title 'Prayer times for prayer' is misleading and contradicts the description, which reduces clarity and may confuse an agent. It is not well distinguished from sibling tools like prayer_search or prayer_verse.

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 provides no guidance on when to use this tool versus alternatives. It does not mention when to omit the book parameter, when to use a specific book, or how this differs from other prayer-related search tools. There is no explicit context or exclusion criteria.

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