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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower, yet the description adds real behavior: the ordered sequence of screens applied and the fact that results link to halal alternatives. It does not disclose response format or timing, but the added process detail is substantive.

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 body is short and dense with real information, but the leading 'Halal or Not. Is this stock halal?.' duplicates the title verbatim and pushes the actual substance to the third sentence. Two of five fragments do not earn their place.

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?

No output schema exists, and the description compensates by indicating the result is a per-standard screening plus links to halal alternatives. For a one-parameter, read-only tool that is nearly complete; only the precise verdict shape remains unstated.

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%, so baseline is 3, but the description extends the single parameter beyond the schema's 'US stock ticker' by noting a company name also works with concrete examples (nvidia, philip morris). That is genuine added meaning about accepted input formats.

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 gives a specific verb and resource ('Screens a US-listed stock') plus the methodology (business screen, then AAOIFI/Dow Jones/S&P/MSCI debt screens), which separates it from siblings like halalornot_check_crypto or check_fund. The opening two fragments merely restate the title, and it never explicitly contrasts with mizan_screen_company or halalornot_ask_is_it_halal, so it stops short of 5.

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?

'A company name also works (nvidia, philip morris)' gives useful input guidance, and the mention of links to halal alternatives hints at follow-up flow. But there is no statement of when to pick this over the sibling screeners (mizan_screen_company, halalornot_ask_is_it_halal) or any exclusion, so usage is only implied.

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