cos_trajectory_read

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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful context by listing the kind of content returned (phase, current focus, architectural decisions, anti-patterns, open questions) and by framing it as a session-start snapshot, which goes beyond the 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 front-loaded with the core purpose, followed by a clear use case, then structured Args and Returns sections. Every sentence adds value and there is no redundant information.

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 tool with one parameter and an output schema, the description covers purpose, usage timing, parameter semantics, and return shape. The inclusion of the return JSON structure makes it self-sufficient even without the output schema.

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 schema only defines 'limit' as an integer with default 1; the description adds the accepted range (1-20) and clarifies that it controls the number of recent snapshots. This fully compensates for the 0% schema description coverage.

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 uses a specific verb-resource pair ('Return the most recent project trajectory snapshot(s)') and clearly defines the tool's scope. It also distinguishes itself from the task-board tools by stating it should be used to understand project direction before looking at the task board.

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 gives explicit usage context: 'Use at session start to understand WHERE the project is heading before looking at the task board.' It does not mention when not to use the tool or name direct alternatives, but the context is clear and actionable.

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