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

Annotations already cover read-only/idempotent/non-destructive, and the description goes well beyond them: newest-first ordering, the authentication prerequisite ('Requires connecting a Valet account'), the ownership constraint (sessions belong to agents, not sites/apps), and a PII handling instruction for titles.

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?

Four sentences, front-loaded with purpose and return fields, followed by sibling routing, PII guidance, and the auth prerequisite. Each sentence carries distinct, callable information with 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?

With no output schema, the description fully enumerates the returned fields, states ordering, discloses the auth requirement, and clarifies scope (agents vs. websites/apps). An agent has everything needed to call and interpret this tool.

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 (name, org_name) and their defaults are already documented. The description adds no parameter-level detail beyond what the schema states; the 'pass a session id' sentence concerns sibling tools, not this tool's inputs.

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 and resource (list an agent's conversation sessions) plus the ordering (newest first) and the exact fields returned. It is immediately distinguishable from its list_* and get_session/destroy_session siblings.

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?

Explicitly routes the agent: 'Pass a session id to get_session to read one, or to destroy_session to delete it,' and adds a when-not condition ('a website or app has none') that tells an agent when this tool is inapplicable.

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