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

With no annotations the description carries the full burden. It does disclose a genuine behavioral trait — deduplication ('lives once and is referenced by key; no duplication') — which is useful. However it omits permissions/auth requirements, what happens on key conflict, and mutation/rollback behavior, leaving meaningful gaps for a write tool.

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?

A single tight sentence with the action front-loaded. The bracketed '[KEEP · door]' tag is unexplained noise, but overall it wastes little space.

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 mutation tool with no annotations, no output schema, and 0% schema coverage, the description is too thin. It neither covers the parameters, the key-collision behavior, nor what the caller gets back, so an agent lacks enough to invoke it confidently.

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 description coverage is 0% for two parameters (key, cards). The description gestures at their relationship ('each entry mints ONE card ... referenced by key'), which implies cards are entries and key is the reference, but gives no format, constraints (maxLength 4000, maxItems 200), or conflict semantics for the key.

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+resource ('Create/extend a shared study'), so an agent knows this writes to a study. The parenthetical 'superposition stack' is jargon and the bracketed '[KEEP · door]' tag adds no meaning, but the core action is discernible and distinct from study_find/study_export/study_import.

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?

No guidance on when to use this versus study_import (which likely also adds content) or study_find. The only hint is the opaque '[KEEP · door]' prefix, which does not tell an agent the conditions for selecting this tool.

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