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

With no annotations, the description carries the full burden and discloses almost nothing. The [PUBLIC READ/WRITE] tag communicates access scope, but it does not say whether an existing key is overwritten, what the default TTL is, whether writes persist across sessions, or what permissions are required for the public scope.

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?

One front-loaded sentence that names the action, resource, and purpose with no padding. The bracketed access tag is compact and useful, though it sits ahead of the actual verb and slightly delays the payload.

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?

A six-parameter mutation tool with a nested object value, no annotations, and no output schema needs more than this: overwrite semantics, TTL behavior, and what a caller gets back are all unstated. The description is not adequate for the tool's complexity.

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% with all six parameters documented, so the baseline is 3. The description adds no extra meaning about key namespacing, ttlMs defaults, or how tokenCountEstimate/isStatic affect cache behavior.

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 (store) and a precise resource (KV Prompt Cache item), and even frames the benefit (session context, token savings). The put/get pairing with the sibling get_kv_cache_item is inferable from the names, though the description never states it 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?

The word 'Explicitly' hints that this is the deliberate manual-write path, but there is no statement of when to use it versus letting the cache populate automatically, or versus get_kv_cache_item, query_kv_cache_stats, or clear_kv_cache_memory. No prerequisites or exclusions are given.

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