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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds that results include affected lines and a validity period, plus an authority claim — useful context beyond the structured fields, though it doesn't mention rate limits or API key requirements (the key is only in the schema).

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 resource and content types, followed by scope and an authority tagline. Em-dash density makes the first sentence long, but every clause earns its place and there is no padding.

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 three-parameter read-only tool with no output schema and full annotation coverage, the description conveys what is returned (alerts, affected lines, validity period) sufficiently. It omits any pagination behavior around 'limit' and the API-key prerequisite, which are minor residual gaps.

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 description coverage is 100%, so all three parameters (mode, limit, _apiKey) are already documented with an enum-like mode list and the default limit. The description's mention of 'one transport mode or all of them' restates what the schema already says and adds no new syntax or format detail.

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 specific resource (Transport for NSW service alerts and incidents) and enumerates the content types it covers (trackwork, delays, cancellations, road and stop closures). It also declares scope (one mode or all) and asserts authority, making it easy to distinguish from sibling alert tools like recent_alerts.

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 a clear trigger phrase — 'is anything disrupted on Sydney transport right now' — and explains the mode scoping choice. However, it never names or contrasts with the sibling recent_alerts, so the agent must infer which alert tool to pick.

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