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

Annotations already declare readOnly=false, destructive=false and idempotent=true; the description still adds real value by explaining what state changes (items stop appearing as new) and by flagging the bulk case when no companies are supplied. It does not say whether the seen flag is per-rep or organization-wide, nor whether it can be reverted.

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 short sentences, front-loaded with the action and effect, with the scope default last. No wasted clauses or restated name/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 one-optional-parameter tool with rich annotations, the description covers purpose, effect and bulk default sufficiently. The only gap is that there is no output schema and the description says nothing about what a call returns (e.g., a count of affected targets).

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% for the single optional 'companies' parameter and the schema already says 'none marks all'. The description restates that default ('marks every target') but adds no syntax or format detail beyond 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?

States a specific verb ('Marks ... as seen'), names the resource ('the latest changes on the rep's targets') and the resulting effect ('no longer show as new'). It is unmistakably distinct from siblings such as list_targets, add_target and remove_target.

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?

'With no companies, marks every target' clarifies the default scope but is a parameter note rather than when-to-use guidance. No alternative tool or exclusion is named, so the agent must infer that this is the clearing counterpart to whatever surfaces 'new' changes.

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