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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), but the description adds genuinely useful behavior: the feed is Nasdaq-sourced and refreshed every minute, which markets are covered, and the possible status values (halted, resuming_soon, resumed). It stops short of noting rate limits or staleness caveats, so 4 rather than 5.

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 core resource and scope, then return fields, then filtering. Information-dense with little waste, though the first sentence is long and clause-heavy rather than tightly structured.

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?

With no output schema, the description enumerates the return fields (symbol, market, plain-English reason, halt time, resume time, status) and discloses freshness (refreshed every minute) and source. Nothing an agent needs to invoke this read-only, single-param tool correctly is missing.

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% and the single optional parameter is fully documented in the schema itself. The description's 'filter by one or more tickers, or omit for all' merely restates that, adding no format or syntax detail beyond what is already structured.

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 resource (US stock trading halts) with explicit scope (right now and earlier today, Nasdaq/NYSE/NYSE American), names the data source (Nasdaq halt feed), and enumerates the returned fields. An agent can distinguish it from siblings like why_is_it_moving without opening the schema.

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 description says how to filter (by tickers, or omit for all) but never states when this tool is the right choice versus alternatives such as why_is_it_moving, nor any exclusions. Usage is implied by the real-time halt framing rather than stated.

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