Market status

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

Annotations already declare read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description adds genuinely useful context beyond that: which markets are covered, which index symbols are surfaced per market, and the regular-session windows with explicit timezones (Africa/Cairo, America/New_York). It stops short of holiday/exception handling.

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 primary output (open/closed status) before expanding into session times and index lists, and the second sentence isolates the trading-hours reference data. Dense but every clause carries information; the ellipses in the index examples are the only slightly loose element.

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 carries the return-value burden and largely does so: status, session times, and benchmark symbols. Timezones are given for regular sessions, which is the key ambiguity. It omits holiday/half-day handling and what the simulator returns, but that is a minor gap for a status-lookup tool.

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 enum values are already documented, so the baseline is 3. The description adds real meaning on top by mapping each market to the benchmarks returned (Egypt: EGX30/EGX70; US: SPY/QQQ/DIA; UAE: FADGI) and by reinforcing the "not the simulator" qualifier that the schema's simulator entry does not convey.

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 concrete verb+resource (report whether a market is open, session open/close times, and headline indices/benchmarks) and scopes it to three named markets. The parenthetical "not the simulator" actively distinguishes it from the get_markets sibling, so an agent can route without opening a 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?

Gives clear context for when to call it (Egypt/US/UAE market state and benchmarks) and an explicit exclusion ("not the simulator"), but never names the alternative tool an agent should use for the simulator or for broader market listings. The condition that selects a sibling is implied rather than stated.

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