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

Beyond the annotations (readOnlyHint=false, openWorldHint=false), the description discloses the cost model (testers × 15 credits, held in escrow, unused refunded) and an auth requirement ('needs a token'). That is real behavioral context an agent cannot get from the structured fields, though it omits what happens on failure or partial campaigns.

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 clauses, front-loaded with the primary action, then cost model, then the token requirement. No filler and nothing redundant.

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 mutation tool with no output schema and only 2 params, the description covers purpose, cost mechanics, escrow/refund, and auth. It lacks only edge-case behavior (e.g., insufficient credits handling) and how testers interacts with the min/max bounds.

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%: package_name is documented in schema, testers is not. The description ties testers to cost ('testers × 15 credits'), adding some meaning, but never explains the 12–30 bounds or the default of 15. Baseline 3 is appropriate given the partial coverage.

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 ('Start recruiting') and resource ('testers for one of the user's apps'), which is clearly distinct from sibling names like add_testers, set_campaign_status, and join_test. It does not explicitly name a sibling or draw the boundary, so it falls short of a 5.

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?

Usage is implied: you call this to launch recruitment for an app. There is no explicit statement of when to prefer it over add_testers or set_campaign_status, nor any prerequisites beyond the token note. Adequate but leaves the agent to infer the sibling boundary.

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