build_session_registry

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

With no annotations, the description carries the burden, and it does well by disclosing immutability, expiration, and fail-closed behavior without hidden work. It does not detail every side effect, but it adds meaningful behavioral context beyond the schema.

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?

Two concise sentences front-load the core purpose and then add the key fail-closed constraint. Every sentence earns its place with no fluff.

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?

Although an output schema exists and fail-closed behavior is stated, the definition omits parameter meanings, usage alternatives, and side effects beyond immutability/expiration. With no annotations and 0% schema description coverage, an agent still has significant gaps to bridge before invoking 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%, so the description must compensate; 'run workspace' and 'expiring' map weakly to run_dir and ttl_days, but no parameter is actually explained. shadow_canonical, now, and ttl_days semantics remain entirely opaque.

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 names a specific verb ('Finalize') and resource ('run workspace' into an 'immutable, expiring session overlay'), which is far more informative than a tautology and separates this from generic build tools. It does not explicitly compare against siblings, but the overlay/fail-closed language makes the tool's role clear.

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 states a clear precondition: research/review artifacts must already exist, and stages still needing an agent cause failure. This implies the tool should be run only after earlier research stages complete, but it never names alternatives or says when not to use it.

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