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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds real process detail beyond that: it runs a business screen against each standard's excluded industries, then the AAOIFI, Dow Jones, S&P and MSCI debt screens, and returns halal alternatives — useful multi-step and output context.

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?

Front-loaded with the user-facing question, then three tight sentences covering process, accepted input, and output. Every sentence adds something; no filler.

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 one-parameter read-only tool with no output schema, the description covers the screening steps, alternate input form, and a hint at the return (links to halal alternatives). Only the exact result shape and any rate/coverage caveats are left unspecified.

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% for the single ticker parameter, giving a baseline of 3. The description goes further by stating a company name is also accepted ('nvidia, philip morris'), which is meaningfully broader than the schema's 'US stock ticker' wording.

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?

States a specific verb and resource ('Screens a US-listed stock') and clarifies scope (US-listed, via Mizan). The stock-specific scoping plus asset-class framing lets an agent distinguish it from check_crypto and check_fund without opening schemas.

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?

Clearly scoped to US-listed equities and notes that a company name works as input, which covers the main invocation context. No explicit when-not or routing to check_fund/check_crypto, though sibling names make the boundary largely inferable.

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