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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does well: it reveals ordering ('newest first'), output shape ('keys and sizes, not values'), and authentication requirements ('Requires a free API key (Authorization: Bearer tf_...) so entries stay private to you'). It does not mention rate limits or pagination behavior, but these are minor for a list 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?

The description is front-loaded with the core function in the first sentence, followed by usage guidance and then return/auth details. Three sentences carry useful information without fluff. The third sentence packs return behavior and authentication together, which is slightly dense but still efficient.

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 list tool with no output schema, the description covers the essential context: what it lists, how it orders/filters, what it returns, and authentication prerequisites. It does not describe output format or error cases, but those are not required for basic invocation. The sibling set is evident from the context signals, and the description clearly fits into the memory workflow.

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 50%: prefix is documented in the schema, and the description reinforces it ('optionally filtered by prefix'). However, the limit parameter is entirely absent from the description, and the schema only provides min/max/default without explaining its purpose. The description partially compensates for the coverage gap but does not fully explain all parameters.

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 opens with a specific verb and resource: 'List the keys you have stored, newest first, optionally filtered by prefix.' It clearly states what the tool does and differentiates it from siblings memory_get, memory_set, and memory_delete by emphasizing it returns keys and sizes, not values.

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 description gives explicit usage context: 'Use this to discover what a previous session left behind before deciding what to read.' It also implies the alternative (memory_get) by stating 'Returns keys and sizes, not values,' making it clear this is a discovery step rather than a value retrieval step. It stops short of explicitly naming the sibling tool or stating 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.