brain_log

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

With no annotations, the description must disclose behavior on its own. It does reveal that entries are timestamped, stored in a dated markdown file, and that auto-reindexing occurs. However, it does not state whether the entry is appended or overwrites existing content, what side effects reindexing has, or what permissions or safeguards apply.

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 a single front-loaded sentence with no filler; the file-format detail and auto-reindex side effect are economically included. It loses a point because the extreme brevity omits parameter and usage context that the tool clearly needs.

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?

Although an output schema exists so the return value need not be described, the overall definition is incomplete for a three-parameter tool with no annotations and 0% schema description coverage. It does not explain what type means, how agent and message are used, whether the file is appended, or why auto-reindexing matters, leaving an agent under-equipped to call it confidently.

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 description coverage is 0%, so the description must compensate for the three parameters, but it does not mention agent, message, or type at all. The parameter meanings are left entirely to inference from their names, which is inadequate for an agent to know how to fill them correctly.

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 identifies a concrete resource (daily YYYY-MM-DD.md log) and the action of recording a timestamped entry, which clearly distinguishes it from generic brain_write or brain_append. However, it lacks an explicit verb like 'create' or 'append', and the purpose is more inferred from the name than fully stated.

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 implies a daily-logging use case but provides no guidance on when to use brain_log versus brain_write, brain_append, or brain_lesson. There are no stated conditions, exclusions, or references to alternatives, so an agent receives no routing help.

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