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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds genuine context beyond that: the eligibility criteria (debt passing all four standards as of last quarter-end), the sort order (largest first), the inclusion of Shariah index funds for US/UK investors, and a pre-purchase screening step.

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 dense sentences, with the core purpose front-loaded and the screening caveat placed last as an actionable caution. Some qualifier stacking ("or the nearest related one," "for US and UK investors") but nothing that should be cut.

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?

There is no output schema, and the description compensates by describing what comes back (industry-matched permitted companies, rank order, index funds). For a one-parameter lookup this is nearly complete; only pagination/result limits are unaddressed.

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 description coverage is 100% for the single ticker parameter, and the schema already notes it accepts a US listing symbol or company name. The description adds no syntax or format detail beyond identifying the input as "the holding to replace," so baseline 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 verb-implied action (find/return alternatives) and resource (Halal-compliant replacements for a holding), and spells out the return contents: same-industry companies permitted by the four debt standards plus Shariah index funds. It is clearly distinct from screen_company and screen_portfolio, though it never names a sibling explicitly.

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?

Usage is implied rather than stated: the phrase "the holding to replace" and "before buying" convey the workflow (swap a non-compliant holding, verify before purchase). There is no explicit when-to-use/when-not guidance or routing to alternatives like screen_company.

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