cos_timeline

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing the safe, read-only nature. The description adds behavioral context by specifying the lookback window, domain filtering, limit, and the exact structure of returned entries (id, title, date, outcome, type), going beyond the annotation-only safety profile. It does not contradict 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 concise and well-organized: a one-sentence purpose statement followed by clearly structured Args and Returns sections. Every sentence adds value, with no filler or redundancy.

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 simplicity (3 optional parameters, read-only, no side effects) and the presence of annotations and an output schema, the description covers everything needed: what the tool does, how to configure it, and what it returns. It is fully adequate for an agent to invoke the tool correctly.

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 no property descriptions (0% coverage), so the description fully compensates by explaining each parameter: days with range and default, domain with an example, and limit with range and default. This provides complete meaning beyond the bare schema types and defaults.

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 with a specific verb and resource: 'Get recent task outcomes and observations timeline.' It explicitly describes the return format, making the purpose unambiguous. However, it does not explicitly differentiate itself from sibling query tools like cos_task_daily or cos_log_query, so it falls short of a 5.

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 when to use the tool—when a timeline of task outcomes and observations is needed—but does not provide explicit alternatives, exclusions, or context for choosing it over similar tools. There is no mention of 'instead of X' or 'use this when', so the guidance is only implicit.

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