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

Annotations declare the mutation profile (readOnly=false, openWorld=true, non-idempotent, non-destructive). The description adds a genuinely new trait not in structured data: atomicity ('All arrive or none do'). It does not address reversibility, permission requirements, or failure modes, so it falls short of a 5.

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, each carrying distinct information (what, guardrail, atomicity), with the core action front-loaded. No filler.

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 2-parameter mutation with full schema coverage and no output schema, the description covers action, scope, guardrail and atomicity. It omits what a successful response looks like (e.g., whether share ids or a record are returned), a minor gap for an outbound share operation.

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 description coverage is 100%, so both parameters are already documented, and the description only echoes the 'exact address' constraint and the 20-item ceiling that the schema already enforces via maxItems. Baseline 3 is appropriate.

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 ('Send copies'), the resource ('Sixteen Bridges bubbles'), the destination type ('another Sixteen Bridges account') and channel ('by email'), with a bounded scope ('up to 20'). This is clearly distinguishable from siblings like list_shares or move_bubbles 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?

'Only when the user asks, to the exact address they give' gives an explicit trigger condition and a constraint on the recipient value. It does not name an alternative tool (unlike the high-calibration example), but no sibling overlaps meaningfully, so the routing risk is low.

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