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

Annotations already declare readOnly=false, idempotent=true, and destructive=false, and the description usefully adds non-obvious behavior beyond them: saving does not reserve the business (another agency can still sign it first) and 'joined' is set automatically. It stops short of noting what happens on an invalid/missing prospect or what the call returns.

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 tight sentences with the agency precondition front-loaded, then the core action, then two behavioral caveats. No filler; every sentence carries information an agent would otherwise have to infer.

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 an upsert tool with no output schema and partial param coverage, the description covers the essentials: required context (approved agency), action (add/update), status lifecycle, and the non-reservation and auto-join semantics. Only the prospect identifier's format and error behavior are left unspecified.

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 only 33% (only 'note' is documented), so the description must compensate, and it partially does by enumerating status values and mentioning the note. However, the key required 'prospect' parameter is never described (only implied as 'a business'), and the status list merely restates the schema enum, leaving a meaningful gap.

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 ('add a business to its prospect pipeline, or update its status') and covers both the create and update modes. An agent can distinguish this from sibling reads like find_prospects, my_prospects, and prospect_details without opening any schema.

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 a clear precondition ('For an APPROVED agency'), which tells the agent when the tool is callable. However, it never names alternatives (e.g. find_prospects to locate a business first) or states when-not to use it, so routing guidance is implied rather than explicit.

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