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

Annotations already cover read-only, idempotent, non-destructive and closed-world behavior, so the bar is lower. The description nonetheless adds real behavioral detail: the filtering criteria (permitted business, debt passing four standards at last quarter-end) and ordering (largest first), plus coverage of index funds for US/UK investors.

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 identity and purpose, then the criteria and a next-step instruction. It is fairly dense and slightly run-on, but every sentence carries information that helps selection and invocation.

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, so the description must carry return-shape expectations; it does so by describing the result set (same-industry permitted companies, largest first, plus index funds). It is nearly complete, missing only explicit absence/no-match handling or result-count behavior.

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?

With a single parameter at 100% schema description coverage, the schema already fully documents the ticker ('a US listing symbol or company name'). The description adds only the framing 'the holding to replace', which is a baseline-consistent but modest contribution.

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 precise purpose: find companies in the same or nearest related industry whose business is permitted and debt passes all four standards, plus Shariah index funds. It clearly distinguishes itself from siblings like mizan_screen_company or halalornot_screen_stock by being about replacements for a holding.

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 closing line gives a concrete workflow cue ('Screen a pick live with /screen/{ticker} before buying'), which tells the agent what to do after using this tool. However, it does not explicitly compare this tool against sibling alternatives, so when-not-to-use is left implicit.

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