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

Annotations only declare destructiveHint=true, so the description carries the rest of the behavioral burden. It discloses a genuinely non-obvious consequence — a deal with no users is invisible to agents — which the schema and annotations never state. It does not cover permissions or side effects of creating against existing records.

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?

Three short sentences, front-loaded with the core action, then the prerequisite and the critical omission warning. Every sentence carries unique information.

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 15-parameter mutation tool with no output schema, the description covers the two required inputs and one critical behavioral trap but leaves the bulk of optional parameters (pricing, commissions, closing dates) unexplained. Adequate to call the tool for a minimal deal, incomplete for a fully specified one.

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 47% across 15 parameters, so the description must compensate and only partly does: it clarifies where stageId comes from and warns about userIds. The other 13 parameters, including all the commission and date fields, get no explanation beyond sparse schema text.

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 and resource ('Create a deal in a pipeline stage') and adds the scope detail that the stage must come from a pipeline. It does not explicitly distinguish itself from fub_update_deal or fub_list_deals, but the create verb 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?

Gives actionable prerequisites: stage ids must be obtained from fub_list_pipelines, and userIds should be included or the deal becomes invisible. It lacks an explicit when-not condition or a direct comparison to fub_update_deal, so it stops just short of full routing guidance.

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