Read recent log events, newest last. ALWAYS narrow with topic and/or level - an unfiltered tail of a busy bench is noise. topic is exact (cpp.clock) or a prefix ending in a dot (expo.).
| Name | Required | Description | Default |
|---|---|---|---|
| level | No | Minimum level; ERROR is the usual choice when hunting a bug | |
| limit | No | Max events (default 50, cap 200) | |
| topic | No | Exact topic, or a prefix ending in a dot | |
| contains | No | Only events whose text contains this (case-insensitive) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description carries the behavioral burden. It discloses that events are recent, ordered newest last, and that unfiltered queries can produce noisy output, and explains topic matching semantics. It lacks a precise time window definition, but the essential traits are covered.
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 sentences with no filler. The core purpose is front-loaded, and the narrowing rule and topic format each earn their own sentence.
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 tail tool with no output schema, the description covers purpose, ordering, filtering guidance, and topic format. The only minor gap is that 'recent' is not defined as a time window, which is acceptable for a tail utility.
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%, so the baseline applies. The description reinforces using level and topic for narrowing and gives an illustrative example for topic matching, but it adds no parameter semantics beyond what the schema already documents.
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?
States a specific verb and resource ('Read recent log events') and specifies ordering ('newest last'), which clearly distinguishes it from a historical search tool like search_logs. The purpose is immediate and not a tautology.
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?
Gives explicit guidance to always narrow with topic and/or levelheb, and warns that an unfiltered tail is noise. It does not name alternative tools or when-not-to-use conditions, but the context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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