tail_log

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

With no annotations, the description carries full behavioral disclosure burden. It explains the tool is a read operation (read last N lines) and details modes and the structured parameter, giving insight into behavior. However, it does not explicitly state it is non-destructive or require no special permissions, which is typical for read tools. The provided context is sufficient for a simple log reading 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?

The description is extremely concise: one sentence for the purpose followed by a bullet-style args docstring. No superfluous words. Every line adds value, and the structure is easy to scan. This is an ideal balance of brevity and completeness.

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 purpose is simple (reading log lines) and there is no output schema, the description explains modes, date override, and structured output. It covers the essential usage context. However, it does not detail the output format for unstructured mode, mention potential errors, or prerequisites like terminal selection. For a basic tool, this is mostly complete but has minor gaps.

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 input schema has 0% description coverage, so the description must compensate. The args docstring explains each parameter: mode specifies three valid values (live, journal, tester) and their file paths, lines is the count, date overrides YYYYMMDD, structured parses records. This adds critical meaning beyond the schema types and defaults, making the parameters fully understandable.

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 'Read last N lines from terminal logs,' specifying the verb (read), resource (terminal logs), and scope (last N lines). This distinguishes it from sibling tools like 'list_terminals' (which lists terminals) and 'kill_terminal' (which terminates). The purpose is unambiguous and concise.

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 does not explicitly state when to use this tool versus alternatives. It provides mode options (live, journal, tester) but offers no guidance on when to prefer this tool over siblings like 'list_terminals' or 'select_terminal'. There is no mention of prerequisites or exclusions, leaving the agent to infer appropriate use.

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