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

Annotations already declare this is a non-destructive, idempotent, mutating operation, so the safety profile is covered. The description adds the set-style semantics ('mark or unmark' driven by a boolean), implying repeated calls converge, but says nothing about what favoriting does downstream or whether favoriting an unknown id errors.

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?

A single front-loaded sentence with no filler; the verb pair and resource come first and there is no redundancy with the title.

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 boolean toggle whose annotations already carry mutation and idempotency semantics, the description is close to sufficient. The remaining gap is the untracked-keyword precondition and the true/false mapping, which a caller would benefit from having stated.

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 50% and the description only implicitly maps 'mark or unmark' to the favorite boolean; it never states that favorite=true sets and false clears. The keyword_id parameter's meaning is left entirely to the schema's brief 'Tracking id.' label.

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 pair (mark/unmark) and resource (tracked keyword's favorite flag), which is distinct from sibling tools like track_keywords or untrack_keyword. Slightly less crisp because it never says what a 'favorite' affects in the UI or whether the keyword must already be tracked, but the action is unambiguous.

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?

No statement of when to use this versus alternatives, no prerequisites, and no note that the keyword must already be tracked before favoriting. The word 'tracked' hints at a precondition but the agent must infer it.

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