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

Goes well beyond the annotations: discloses that duplicates are silently skipped, that `added` may be lower than keywords sent, that it can fail with a plan-limit error (a count cap, not a spend cap), and that no rank check or metrics refresh is triggered. This is exactly the operational context annotations cannot carry.

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 purpose, then layers return semantics and free/failure behavior in a compact run of sentences. Dense and largely waste-free, though the plan-limit explanation is slightly long-winded.

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, so the description correctly supplies the return shape ({ added, addedIds }) and its counter semantics, plus follow-up guidance. An agent has everything needed to call it and interpret results.

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 100%, so both parameters are already documented, and the duplicate-skip note appears in both places. The description adds semantics around the `added` output counter rather than the input params themselves, so baseline 3 is appropriate.

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+resource ('Adds keywords to an existing rank tracker config'), immediately distinguishing it from create_rank_tracker, list_rank_tracking_keywords, and remove_rank_tracking_keywords in the sibling set.

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?

Clarifies it operates on an existing config, that it is free/no credits spent, that it does not trigger a rank check, and routes to get_rank_tracker as the follow-up. It stops short of naming explicit alternative tools for other cases, but the context is clear.

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