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

With no annotations, the description carries the full transparency burden and does it well. It explains the output is a 'soul_document' meant for injection, implies the text varies by session orientation ('stillness, precision, or creative expansion'), and states the recommended placement. It doesn't explicitly call out that the operation is read-only, but 'Fetch' naturally implies no side effects, making this sufficient.

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, front-loaded with the core purpose, followed by usage and placement. Every sentence earns its place – no filler or repetition. Perfectly sized for a simple tool.

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 tool is simple (one optional param, no output schema) and the description covers what it returns ('soul_document'), when to call it (session start), and how to use it (paste into system prompt). This is complete for an agent to select and invoke correctly without ambiguity.

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 has 100% coverage with enum descriptions already explaining each session_type value. The description adds contextual color ('stillness, precision, or creative expansion') that maps to the parameter but doesn't add any technical detail beyond the schema. Baseline 3 is appropriate.

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 opens with 'Fetch a ManifestYOU soul document' – a specific verb and resource – and immediately clarifies what that document is ('a short philosophical grounding text'). It clearly distinguishes the tool's role from any other by explaining its unique purpose (system prompt injection before sessions).

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?

Explicit 'when' guidance: 'Call this at the start of a session to orient the model...' and 'Paste the returned soul_document into your system prompt or before the first user message.' No alternatives are mentioned (there are no siblings), so no exclusion guidance is needed; this 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.