list_projects

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

With no annotations, the description carries the burden of disclosing behavior. It adds useful context (only projects with session history, return fields) beyond the tool name. However, it does not explicitly state that the operation is read-only, nor does it mention any potential limitations (e.g., pagination, permissions), which would be more important for tools with side effects. For a simple list, this is acceptable but not exhaustive.

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?

The description is two sentences, front-loaded with the primary action, and includes only relevant details about return values. No filler or redundant phrases.

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?

The tool is simple with no parameters and an output schema. The description explains what the tool returns and its filtering condition, which is complete for this level of complexity. The existence of an output schema covers detailed return structure, so the description doesn't need to enumerate every field.

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 tool has zero parameters, so the schema already fully covers the inputs. The description adds nothing about parameters, but there is nothing to add. Per the rubric, a baseline of 4 applies for zero-parameter tools.

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 begins with a specific verb ('List'), resource ('Claude Code projects'), and scope ('that have session history'). It also enumerates the return fields (slugs, session counts, total size), clearly distinguishing it from sibling tools like list_sessions or get_tree, which operate at different levels.

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 gives clear context by specifying it lists projects with session history, which implicitly tells the agent when to use it (project-level overview). However, it does not explicitly mention alternatives or exclusions, so it falls short of a 5. The context is clear enough that no other tool would be mistaken for this one.

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