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

Annotations already mark this as read-only and non-destructive. The description adds substantial behavioral context beyond that: stale=true semantics, plan tier differences including an upgrade note for Free users, explicit handling of missing readings, and a no-backfill limitation after hours. This is rich, useful disclosure.

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 front-loaded with the core action and then uses every subsequent sentence for a distinct, valuable constraint or alternative. Despite covering several caveats, it remains compact and free of filler or repetition.

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 single-parameter read-only tool with no output schema, the description covers what the data represents, freshness semantics, plan requirements, edge cases, limitations, and sibling alternatives. Nothing important is missing for an agent to decide whether and how to invoke the 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?

The input schema covers the only parameter, tickers, with a description including the max 25 constraint. Since schema description coverage is 100%, the baseline is 3. The description adds context about active U.S. listings but does not meaningfully extend the semantics of the tickers parameter itself.

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 states a specific verb and resource: getting the latest consolidated SIP intraday reading for active U.S. listings, with concrete fields such as last trade, UTC timestamp, session freshness, and bid/ask. It also distinguishes itself from siblings by explicitly directing users to GetLatestClosingPrices or GetStockPrices for settled daily bars.

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 clearly explains when to use this tool versus alternatives: intraday readings here, settled daily bars via GetLatestClosingPrices or GetStockPrices. It also provides plan-based usage context (Pro vs Plus vs Free) and states exclusions such as no after-hours backfill.

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