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

Beyond the readOnly/idempotent annotations, the description adds useful behavioral context: the tool compares against New Runtime's stored knowledge, reuses prior understanding, deduplicates web-derived changes, and is free with no auth required. It also discloses the important nuance that it separates new facts from new angles on known stories.

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 front-loads the usage condition and capability, then follows with benefit, auth status, and an example. It is somewhat dense due to the long colon list, but each sentence contributes new information and does not merely repeat structured fields.

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 two-parameter, no-output-schema tool, the description covers the use case, return content categories, auth status, and gives an example. The main gap is that it implies you must already know a topic even though the `topic` parameter is optional, leaving the no-topic invocation case slightly ambiguous.

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%, so the baseline is 3. The description adds semantic context by explaining that `since` means your last run or report dateaging, and it provides a concrete combined JSON example for both parameters, which helps the agent understand how to invoke the tool correctly.

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 names the action (what changed since a date), the reference frame (against what New Runtime already knew), and enumerates the exact output categories: stronger/weaker patterns, obsolete items, resolved forecasts, new facts vs. new angles, and what still holds. This clearly positions it as a delta-report tool, distinguishing it from broader search or topic-brief siblings.

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?

'Use when you already know a topic and need only what changed since a date' gives an explicit trigger condition and even a realistic use case: 'your last run, a report date.' It does not explicitly name sibling alternatives or state when not to use it, so it falls just short of a 5.

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