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

Explains a non-obvious behavior that the annotations alone only hint at: the code is lazily generated on first request and then persists as the brain changes, which justifies readOnlyHint=false and idempotentHint=true. It also discloses the authorization prerequisite (a connected Phorme account that owns the brain) and what the code does downstream (grants a starting copy of that brain).

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?

Front-loaded with the trigger condition ("Use this when..."), followed by mechanism, effect, and prerequisite in four tight sentences. Nothing is redundant, though the clause about the code being made on first request and kept is slightly clunky in phrasing.

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 single-parameter read tool with an output schema, the description covers the trigger, the side effect of first-use generation, the auth requirement, and the real-world consequence of sharing the code. An agent has everything needed to call it correctly without further inference.

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% and the single brain_id parameter is fully documented, so the schema carries the load. The description only implies that brain_id selects among the coach's brains ("one of their coaching brains") without adding format or sourcing detail beyond that.

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?

States a specific verb and resource: retrieve the shareable code/link for one of the coach's own coaching brains, with a concrete example code format (K7Q2-XR4D). It is distinguishable from siblings like find_coaching_brain (search) and copy_coach_from_code (import), though it never names those alternatives explicitly.

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?

Gives an explicit trigger with a quoted user utterance ("what is my coach code?"), which makes the intended invocation context unmistakable. It stops short of stating when not to use it or which sibling to pick instead (e.g., copy_coach_from_code for someone else's code).

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