zen_save_session

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

The description explains that when urls are given, each origin gets opened briefly in a temp tab to read localStorage. This discloses a behavioral side effect. No annotations are present, so the description carries full burden. It does not mention file overwrite behavior, but core behavior is transparent.

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 very concise: a one-line summary, a use case paragraph, and an Args section. Every sentence adds value without redundancy. It is well-structured and front-loaded.

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 the tool's simplicity (2 parameters, no output schema, no annotations), the description covers the main behavioral aspects. It lacks details on whether the same file name overwrites, but the use case and parameter explanations are sufficient for an agent to understand the tool's purpose and side effects.

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 has 0% description coverage, so the description must compensate. It fully explains both parameters: 'name' becomes a filename under ~/claude-zen-sessions/, and 'urls' specifies origins whose cookies and localStorage are snapshotted with the note about temporary tabs.

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 clearly states the tool snapshots cookies and per-origin localStorage to disk. It provides a specific use case (login once, save, load for parallel agents) and distinguishes from siblings like zen_load_session and zen_cookies.

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 a clear use case for when to use this tool (saving authenticated sessions for later use by parallel agents). While it does not explicitly list alternatives or when-not-to-use, the context implies that zen_load_session is for loading and zen_cookies for manipulating cookies directly.

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