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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds only the tenant-scoped boundary and a resource list; it never states what invoking the tool actually does to an estimate or line, leaving the central behavior undisclosed.

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?

The single sentence is short, but its length comes from an undifferentiated list of resources, not from informative content. It front-loads a vague verb and does not earn its place because none of the listed resources are tied to the add-line action.

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 tool with 13 parameters, nested objects, an output schema, and many siblings, this description is drastically incomplete: no action, no prerequisites, no parameter guidance, and no selection criteria. The output schema cannot compensate for not knowing when or how to invoke the tool.

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?

With only 15% schema description coverage and core parameters like line/lines/estimate_id undocumented, the description needed to compensate but remains silent on parameter meaning. 'Tenant-scoped' loosely maps to tenant_id but gives no help for the line object(s), query, bridge, or format fields.

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 uses the generic verb 'Operate' and lists an overly broad set of resources (drafts, lines, versions, documents, exports, policy receipts) without ever stating that this tool adds a line to an estimate. This fails to distinguish it from siblings like estimator_estimate_update_line or estimator_estimate_export. It is only marginally better than a tautology because it names the domain.

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 statement of when to call this tool or when not to. The broad wording 'Operate on drafts, lines, versions, documents, exports, and policy receipts' actively implies a much wider scope than add_line, which could mislead selection among the estimator_* siblings.

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