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

With no annotations, the description carries the burden of disclosing behavior. It does disclose the auto-session behavior, which is useful. However, it omits what happens when neither project_id nor project_name is provided, and the simplification 'just pass project_name and content' neglects the required event_type, which could mislead the agent. There is no contradiction with annotations.

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 short and front-loaded with purpose, but the second sentence is partially inaccurate ('just pass project_name and content' while event_type is required). This reduces the reliability of the conciseness, making it less effective than a fully accurate brief description.

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?

The description covers the auto-session use case well but does not explain when to provide an explicit session_id, nor does it mention the required event_type parameter. With no output schema and six parameters, this is a moderate gap. It is sufficient for a simple logging tool but leaves key scenarios unaddressed.

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 100%, so baseline is 3. The description adds value by explaining the relationship between session_id and project_name, emphasizing the auto-session behavior. This goes beyond the individual schema descriptions, clarifying how the parameters interact.

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 the tool's function ('Log an activity or event') with a specific verb and resource. It implies distinction from sibling tools like log_trace by focusing on activities/events, but does not explicitly name alternatives. This is clear and somewhat differentiates.

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 provides concrete usage guidance: 'If no session_id is provided, a session is automatically created or reused for the project' and 'no need to start a session first.' This tells the agent when it can skip start_session. However, it gives a slightly misleading 'just pass project_name and content' instruction, ignoring the required event_type parameter, and does not mention when to use this tool over log_trace.

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