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

Annotations already signal destructive and read-only status, but the description adds concrete side effects (notes, session-image/battlemap attachments destroyed) and the permission requirement. This is exactly the extra context the rubric rewards.

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 main action and scope, then permissions and confirmation. Every clause adds a new piece of information with no redundancy.

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?

A single parameter, a clear side-effect list, permission requirements, and confirmation guidance make the description self-sufficient. The output schema exists, so return-value details are unnecessary.

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?

The schema covers 100% of the single id parameter with a description ('Mongo _id of the session'). The description repeats 'by id' but does not deepen the semantics, so 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?

Clearly states the specific action ('delete'), the resource ('session'), and the identifier ('by id'), and enumerates included side effects like notes and attachments. This distinguishes it from sibling delete tools by naming the exact resource type.

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?

Provides clear context: the required permission ('contribute') and the instruction to confirm with the user first. It does not explicitly list when-not-to-use or name alternative tools, so it stops short of the 5 threshold.

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