Local Codex work sessions

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

Adds significant context beyond annotations: reads an undocumented index file directly, exposes only three specific fields, and does not provide live/idle status or working directory. Annotations already say readOnlyHint/idempotentHint/destructiveHint, and the description expands on the data source and limitations without contradiction.

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?

Three compact sentences: action, rationale, limitations. No redundant fluff, every sentence adds value.

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 simple read-only list tool with one optional parameter and no output schema, the description sufficiently explains purpose, data source, return contents, and limitations, making it complete for the agent to select and invoke correctly.

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% with `limit` fully described (default, min, max, ordering). The description adds no new parameter details, but the schema handles it; baseline 3 is appropriate.

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 states it lists recent local Codex CLI sessions, specifies the source (sessions `codex resume` picks from), and distinguishes from siblings by noting it reads the session_index.jsonl index directly and what fields it exposes.

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?

Explains when to use this tool: to get a scriptable list of sessions for `codex resume`, and why not to use `codex resume` itself (interactive-only). It also sets exclusions: doesn't expose live/idle status or working directory, guiding the agent to not expect those.

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