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

With no annotations, the description must carry the full behavioral burden. It does signal a destructive operation and reveals the backing store (Redis), but says nothing about whether deletion is idempotent, what happens if the sessionKey is absent, whether the project's other state is affected, or any permission requirements.

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 front-loaded sentence with zero filler; the destructive verb leads and the scope qualifier follows immediately.

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 simple 2-parameter mutation with no output schema, the definition is barely adequate: it omits the outcome of the call (success indicator, behavior on a missing key) and any interaction with sibling state tools, which matters for a destructive operation carrying no annotations.

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 100%, so both projectSlug and sessionKey are already documented in the schema. The description adds no format, scoping, or example detail beyond what the schema provides, which is the baseline expectation.

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?

Uses a specific verb pair (Clear/Delete) with a precise resource (session state stored in Redis for stateful simulation). An agent can distinguish this from set_state/get_state without opening any schema, though the description never names those siblings 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?

Usage is only implied via 'for stateful simulation' — the reader must infer that this applies to sessions created by set_state. There is no explicit when-to-use, when-not-to-use, or named alternative (e.g., that leaving state intact is the default).

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