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

Goes well beyond the annotations: discloses the billing cost ('spend credits again, one per page read'), the polling frequency, the catch-up diff behavior of the first check after a long pause, and the subtle split between the stored status field and whether checks will actually run (weekly check vs creditPaused). The no-op/'alreadyActive' claim is consistent with idempotentHint=true rather than contradicting it.

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-loads the action and the pause_source anchor, then layers cost, idempotency, and status semantics in decreasing priority. It is dense rather than padded, though the credit-paused explanation is long-winded enough to risk burying the actionable parts.

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?

With no output schema, the description carries the return-value burden itself and does so: it names the alreadyActive and creditPaused states and explains what status actually represents. Nothing an agent needs before calling or interpreting the result is missing.

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?

Only one parameter and schema description coverage is 100%, so the schema already explains sourceId fully. The description adds nothing about the ID's form or provenance, which is acceptable at this coverage level but earns only the baseline.

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 verb and resource ('start monitoring a paused page again') and immediately anchors it against the sibling pause_source as its counterpart. An agent can distinguish it from add_source, get_source, and pause_source without opening any schema.

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?

Explicitly defines the trigger condition (a paused page) and the degenerate case ('already monitored is a no-op, reported as alreadyActive'), and routes to get_credit_balance as a precondition check. It does not explicitly say to use add_source when the page was never monitored, so the boundary with that sibling is left to inference.

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