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

The description adds substantial behavioral context beyond annotations: 'Costs 2 credits ($0.04 USDC),' 'Bearer auth required,' '1-hour rolling cache; sub-second when warm,' and clamping behavior. It also describes the event structure. Annotations indicate readOnlyHint=false, but the description does not discuss potential side effects beyond billing, which is a minor gap. No contradiction with annotations.

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 efficiently structured: it opens with the primary purpose, enumerates sources, then covers parameters, event structure, value, cost, auth, and caching. Each sentence adds distinct information with no fluff, making it appropriately sized for a tool with one parameter and multiple behavioral facets.

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?

Given the tool has no output schema, the description compensates by specifying event fields ('type, timestamp, severity, and structured data') and the time-sorted feed order. It also covers cost, auth, caching, and parameter behavior. It lacks details on response envelope or pagination, but for an event stream with simple input, it 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 already fully describes the 'since' parameter with 100% coverage, including defaults and clamping. The tool description repeats this information without adding new meaning. Baseline of 3 is appropriate since the schema carries the burden; the description adds no extra semantics.

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 clearly states the tool's function: 'Aggregates time-stamped events from 4 sources into one time-sorted feed,' naming specific sources (USGS, Hacker News, Polymarket, space launches). This specific verb+resource scope distinguishes it from sibling tools like tf_earthquakes or tf_hf_trending, and the value proposition 'Saves an agent from polling 5 separate upstream feeds' reinforces its unique role.

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 provides clear context for when to use the tool: it is 'for monitor agents' and consolidates multiple feeds, saving polling time. However, it does not explicitly name alternatives or state when not to use it (e.g., when only one source is needed). The guidance is implied rather than explicit, so a 4 is appropriate.

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