market_status

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states 'Local, no network' (indicating a local calculation with no network dependency) and gives the exact trading hours and timezone. However, it does not mention potential edge cases like holidays or weekends beyond the specified weekdays, nor does it describe the return value (e.g., boolean). This is adequate but not comprehensive for a tool with zero annotation coverage.

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?

The description is a single, tightly packed sentence that leads with the core question, then provides the specific schedule and a note about locality. Every word contributes value; there is no fluff or redundancy.

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 zero-parameter tool with no output schema, the description covers the essential context: the market, the time window, the timezone, and the local no-network behavior. It could be improved by noting that the result is a boolean or by acknowledging holiday handling, but given the simplicity of the operation, the description is nearly complete.

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?

The input schema has zero parameters and schema coverage is 100%, so there is nothing for the description to add about parameters. Per the rubric, a baseline of 4 is appropriate when there are no parameters to document.

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 uses a specific verb ('Is') with a clear resource ('Tehran market') and precise conditions (Sat–Wed 09:00–12:30 Asia/Tehran). It immediately distinguishes itself from siblings like session_status or get_quote by focusing on a single market's open/closed state, so an agent can tell them apart without deeper inspection.

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 implies when to use it (to check if the Tehran market is open) but does not explicitly state when not to use it or mention alternatives such as session_status, which likely covers a broader market session status. There is no exclusion or routing guidance, leaving some ambiguity for an agent deciding between this and a sibling.

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