whats_new

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

With no annotations provided, the description carries the full burden and delivers richly: it states 'Read-only; no side effects, auth, or rate limits,' warns that invalid `since` formats throw, explains the mtime-driven caveat for hard-deleted files, and discloses the return value including `total_est_tokens`. This is exemplary transparency.

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 dense but every sentence earns its place: the core action is front-loaded, followed by format specs, safety profile, return insight, caveat, defaults, and a usage hint. There is no repetition or filler.

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 read-only list tool with no output schema, the description covers the full context: when to use it, how to format parameters, what it returns, its safety, and its limitations. An agent can confidently select and invoke this tool based solely on this description.

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% for all four parameters, but the description adds significant meaning beyond the schema: it explains `since` accepts both ISO-8601 and relative durations, clarifies the distinction between `project_id: null` and omitting it, and states defaults for `include_tags` and `limit`. This goes above the baseline of 3.

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 opens with a specific verb+resource+scope: 'List files created or modified since a checkpoint.' This clearly distinguishes it from sibling tools like list_files (which probably lists all files) and search (which might be content-based). No ambiguity.

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?

It provides a clear when-to-use: 'Use at session start to catch up,' and a when-not via the caveat 'hard-deleted files are NOT surfaced.' However, it does not explicitly name an alternative tool for when a different behavior is needed, like search or list_files, so it falls just short of a 5.

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