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

With no annotations, the description carries the entire behavioral burden. It does disclose that results include status and cost info, but says nothing about ordering ('recent' is undefined), how pagination behaves, default result volume, or any auth/permission requirements for the authenticated project.

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?

A single well-formed sentence with no filler and the key scope ('authenticated project') front-loaded. Its brevity edges into under-specification, which is captured in other dimensions rather than penalized here.

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 read-only list tool with no annotations and no output schema, the description covers purpose and partial return content but omits ordering behavior and pagination semantics. It is minimally adequate rather than complete.

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% (page and page_size are both documented with defaults and bounds), so the baseline is 3. The description adds no parameter meaning beyond what the schema already provides.

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?

The description states a specific verb and resource ('List recent sessions') and scopes them to 'the authenticated project', plus it previews the payload ('status and cost info'). It does not explicitly distinguish itself from sibling get_session, so it falls short of the top mark.

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 only implied: 'List recent sessions' naturally contrasts with the singular get_session, but no when-to-use, when-not-to-use, or alternative (e.g. get_session for a single session) is named. An agent can infer the listing intent but gets no routing guidance.

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