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

Annotations already declare it is a non-readonly, non-idempotent, non-destructive mutation, and the description adds real value on top: the 1000-keyword cap, the five-keyword free-account quota, and the fact that rank data arrives after saving. That post-save data-fill behavior is genuinely useful context an agent would otherwise not know.

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?

Two tight sentences, zero filler, with the primary action and limits front-loaded ahead of the quota and async-fill details.

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?

No output schema exists, and the description compensates by explaining that rank data is populated after save and stating the quota constraints. For a two-parameter mutation this is close to complete, with only the trackedAppId provenance left underspecified.

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 0%, so the description must carry parameter meaning. It partially does—clarifying the terms cap and that trackedAppId represents one country row—but leaves the per-term 200-character limit and the exact meaning of trackedAppId (an internal row ID vs. an app/store identifier) to the bare schema.

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?

Specific verb+resource ('Add ... keywords to a tracked app row') with a useful scope clarifier that the row is per-country, which distinguishes it from add_tracked_app. It does not explicitly contrast with get_tracked_keywords, so sibling differentiation is implied rather than stated.

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 implies when to use it (adding keywords to an existing tracked app) but never states prerequisites such as needing an existing trackedAppId or points to get_tracked_keywords for reading existing entries. Usage is inferable but not guided.

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