ck_fs_ls

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

Despite no annotations, the description clearly states 'Read-only — no files are modified', which is the key behavioral trait. It could additionally mention edge cases (e.g., permission errors, symlinks) but is sufficient for a simple listing tool.

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?

Two clear sentences plus a bullet-like list of usage guidelines. Every sentence is purposeful: purpose, safety guarantee, parameter usage, and sibling differentiation. No fluff.

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?

Given no output schema and no annotations, the description covers purpose, safety, parameter usage, and tool selection. It does not explain behavior on invalid paths or output format, but the sibling differentiation and clarity make it mostly complete for the use case.

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 description adds meaning to the 'path' parameter ('relative directory path to list; omit to list the project root') beyond the schema, which only defines type string. For 'project_root' and 'session_id', the schema descriptions are adequate; description does not repeat them. Overall, the description compensates for the 67% schema coverage by clarifying the primary parameter.

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 'List files and directories inside the bound project root' with a specific verb ('List') and resource ('files and directories'). It distinguishes from sibling tools (ck_fs_find, ck_fs_read, ck_fs_grep) by explicitly stating their use cases.

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 provides explicit guidance on when to use this tool ('Use ck_fs_ls to browse directory structure') and when to use alternatives ('Use ck_fs_find to locate files by name fragment', etc.). This leaves no ambiguity about tool selection.

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