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

With no annotations, the description carries the full burden and does well: it explains that each point carries its scan depth, that a null position means the extension was not found at that depth, and that one term tracked in multiple store languages yields one series per language. It discloses the account prerequisite. It does not cover rate limits, pagination, or ordering of returned series.

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 core statement, then two short paragraphs of semantics and one of prerequisites. Every sentence carries information, though the depth explanation is a touch discursive for a definition.

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?

There is no output schema, so the description must convey return shape; it does so by describing series granularity, the depth field, and null-position semantics. Combined with an 80%-covered five-parameter schema, an agent has enough to call it correctly, though ordering and volume of results remain unspecified.

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 80%, so the baseline is 3, and the description adds genuine meaning on top: the depth/pool-size framing justifies the ranking values, and 'one series per term per store' clarifies how term, store, and locale combine into output series. It does not add format or canonicalisation details beyond what the locale schema entry already provides.

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 and scope: 'Daily search position history for an extension's tracked keywords, one series per term per store.' An agent can tell this is a historical ranking-series tool, not a SERP fetch or a metrics tool. It does not explicitly differentiate itself from siblings like get_keyword_serp or get_metrics_history, so it falls short of a 5.

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 real conditional: it needs an ExtensionDash account, and without one the agent should fall back to find_listing or get_store_listing for current store pages. That is explicit when/when-not routing. It never states when to prefer this over get_keyword_serp or get_metrics_history, so it is not a full 5.

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