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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds genuinely new context: the >10% threshold that defines 'significant', the chronological alert-feed shape with summary, entitlement via RivalSweeper plans, and the billing rule (2 credits, no data = no charge). Those are facts the agent cannot derive from annotations or schema. It does not mention rate limits or auth mechanics beyond plan inclusion.

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?

Three tight sentences, front-loaded with the qualifying thresholds, then return shape, then window and billing. Nothing is redundant, though the plan/credit sentence is commercial metadata rather than invocation-relevant content.

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 read tool with no output schema, the description supplies the alert-feed return shape, the significance thresholds, and the look-back window bounds. The main remaining gap is disambiguation from the near-identical moves/predictions siblings.

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 schema already documents both 'domain' (with example) and 'days' (min 1, max 90, default 7). The description restates the window range and default without adding format or semantics beyond it. Baseline 3 applies when the schema carries the parameter burden.

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?

Names a specific resource (significant competitor changes) and enumerates exactly what qualifies: price moves >10%, new promotions, stock-status flips. That threshold specificity makes the tool's output scope unambiguous. It stops short of naming how it differs from the closely-related siblings get_competitor_moves_feed and get_predicted_competitor_moves, so it is clear but not fully differentiated.

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 says what the tool surfaces but never states when to reach for it instead of get_competitor_moves_feed, get_predicted_competitor_moves, or get_discount_frequency_and_depth. The only 'guidance' is the window parameter and plan/credit notes, which are availability facts rather than usage routing.

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