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

With no annotations, the description carries the full disclosure burden and does so well: it reveals cross-session visibility with the same API key, the API key requirement and Authorization header format, privacy isolation, and null behavior for nonexistent keys. This is substantial behavioral context beyond the minimal 'read a value' phrasing.

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?

Three short sentences: purpose, missing-key behavior, and auth/privacy requirements. Every sentence contributes actionable information, and the most important purpose is front-loaded with no filler.

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 one-parameter read tool with no output schema and no annotations, the description is nearly complete: it covers what it does, missing-key behavior, authentication, and privacy scope. It could go slightly further by explicitly stating that the returned value is exactly what was passed to memory_set, since no output schema defines the return shape.

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%, so the baseline applies. The schema already documents 'key' as 'The key to read'; the description adds only the nuance that the key was previously used with memory_set, which is mild added context rather than essential parameter documentation.

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 states a specific verb and resource: 'Read back a value' that was 'stored earlier with memory_set.' It clearly distinguishes this from siblings like memory_set, memory_delete, and memory_list by focusing on reading a single value by key, reinforced by the null-on-missing-key behavior.

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 gives clear context: use this after a value was stored with memory_set, and it explains the null result for missing keys. It does not explicitly mention alternatives, e.g., using memory_list to discover keys when the key is unknown, so it stops short of full when/when-not coverage.

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