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

Annotations already establish the safe read-only, idempotent, open-world profile, so the description's burden is lower. It adds real behavioral context the annotations don't: result composition (stocks plus index funds), sort order (largest first), and the recency constraint (last quarter-end). It does not state result count or pagination.

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?

Two sentences, front-loaded with the outcome and the screening criteria, followed by a short call to action. The criteria sentence is dense and nested but every clause carries selection-relevant information.

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 read-only lookup with one simple parameter and no output schema, the description covers what the results contain, how they are filtered, and in what order. Missing only secondary details like result limits or pagination.

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 the single ticker parameter at 100% coverage, including that it accepts a US listing symbol or company name. The description adds no further meaning about the parameter, so the baseline of 3 applies.

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 a specific output (halal alternatives) and enumerates the exact criteria: companies Mizan covers in the same or nearest related industry, business permitted, debt passing all four standards at last quarter-end, ordered largest first, plus Shariah index funds for US/UK investors. This is precise enough to distinguish it from sibling screen tools.

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?

'Screen a pick live with screen_company before buying' explicitly names the complementary sibling and the workflow step that follows. It gives clear when-to-use context but no explicit exclusion of when this tool is the wrong choice.

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