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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds significant behavioral context: the tool is deterministic ('Deterministic facts'), the prose is the assistant's responsibility, and the framing is the server's. It also discloses the return content (facts plus template) and the limits of what it does not provide.

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 detailed and somewhat long, but every sentence serves a purpose: purpose, workflow, limits, and next step. It is front-loaded with the primary purpose and clearly structured into two steps. Slightly verbose but not wasteful.

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 complexity (8 params, output schema, sibling tool), the description is complete. It tells the agent exactly what to do, what to expect, how to proceed to step 2, and what constraints apply. Nothing essential is missing for an agent to call it 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?

Schema coverage is 100% – every parameter has a description in the schema, so the baseline for parameter semantics is 3. The tool description does not add parameter-specific information beyond that, but it doesn't need to since the schema is comprehensive and includes ranges and examples.

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 specific role: 'Step 1 of 2 for a personality sketch' that casts the chart and returns facts plus a fill-in template. It distinguishes itself from sibling compose_sketch by naming it as step 2 and specifying the task division (deterministic facts vs. assistant's prose).

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?

It explicitly describes the workflow: cast the chart, receive facts/template, write three texts, then pass them to compose_sketch. It also specifies what not to do (no strength verdict, no favorable elements, no Ten Gods, no luck-cycle reading), giving clear boundaries.

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