session_start

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

Discloses behavioral trait: saves a session start marker so session_end can compute duration. This is a mutation side effect. Also lists all returned data types comprehensively.

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 sentences: first states purpose and replaces alternatives; second lists returns and side effect. Front-loaded, 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 complexity (many return items, no output schema), description exhaustively lists returns and side effect. Complete for agent decision-making.

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 coverage is 100%, and description adds rich context for each parameter (e.g., focus surfaces lessons, author enables team telepathy, workspace_path reads git log). Adds value beyond schema.

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?

Clearly defines it as a single-call session briefing for start of session, replacing multiple separate calls. Distinguishes from siblings like smart_recall and recall_best_solution by naming them explicitly.

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 instructs to call at start of every session instead of multiple separate calls. Also notes it saves a marker for session_end, providing clear when-to-use and alternative avoidance.

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