get_principal_notifications

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), so the bar is lower. The description still adds genuinely new behavior: it errors when LINEAR_PRINCIPAL_TOKEN is unconfigured or resolves to someone other than LINEAR_PRINCIPAL_ID, and it notes the payload mirrors `notifications`.

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 front-loaded sentences that state what it reads, why it is separate from the sibling, and when it fails; nothing is redundant. The em-dash stacking makes it slightly denser than necessary, keeping it out of the top band.

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?

An output schema exists so return values need not be described, and annotations carry the safety profile. What remains — identity/principal semantics and the token-resolution error conditions — is exactly the context an agent needs before invoking, and it is all present.

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% (all four params documented, including defaults and formats), so the schema does the heavy lifting. The description adds only the hint that the shape matches `notifications`; it gives no additional parameter semantics. Baseline 3 applies.

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 resource (the principal's inbox) and immediately distinguishes it from the sibling `notifications`, which reads this identity's own inbox. The sentence 'Same shape, deliberately a separate tool rather than a parameter' makes the boundary with the sibling unambiguous without opening either 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?

The description names the alternative (`notifications`) and the condition that selects it ('a different person's notifications'), plus the failure conditions under which this tool must not be used. It stops short of an explicit trigger phrase such as 'use when acting on behalf of the human', leaving a small amount of inference.

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