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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered structurally. The description adds one genuine behavioral fact not in the annotations: intent is estimated when omitted. It does not disclose what happens on a duplicate keyword, whether this triggers ranking/scan work, or any quota limits, so it adds some but not rich context.

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 sentences, front-loaded with the purpose, then the parameter contract. No filler, no restatement of the tool name or title, and the most decision-relevant fact (required vs optional fields) is stated compactly.

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 four-parameter add tool with no output schema and annotations already covering the safety profile, the description covers the essentials: required fields, the intent enum, and the omission behavior. It is only short on edge cases such as duplicate keywords, limits, and downstream effects, which keeps it from a 5.

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 baseline is 3, but the description adds real value: it supplies the four intent enum values (informational|commercial|transactional|navigational) that the schema lacks entirely (schema only says 'Optional intent'), and it states the estimation fallback when intent is omitted. The required/optional split merely restates the 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?

The description states a specific verb and resource: 'Track a new keyword for a site.' This is unambiguous and distinct from the read-oriented siblings (get_keyword_rankings, get_keyword_gaps) and from other add_* tools by resource. It does not explicitly contrast itself with siblings, but the verb+resource is clear enough that an agent can route correctly.

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?

There is no when-to-use guidance, no prerequisites (e.g., the site must already exist / site_id must be valid), and no mention of alternatives such as importing keywords in bulk or the related add_rank_alert. The agent is told what the tool does but not when it is the right choice over siblings.

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