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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered and the bar is lower. The description adds genuine value by disclosing the dual behavior (retrieve vs. list-all-keys when omitting the argument) and the scoping to the agent's identifier (anonymous IP, BYO key hash, or account ID). No contradiction with annotations.

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 sentences with zero waste: core action first, then usage context with examples, then scoping and sibling pairing. Every sentence earns its place, and the key behavioral distinction (omit key to list all) is front-loaded.

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 low-complexity read/list tool with annotations carrying the safety profile and a schema fully documenting the parameters, nothing an agent needs to call it correctly is missing. The dual behavior, scoping, and sibling relationship are all covered despite the absence of an output schema.

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 the schema fully documents all four parameters (which are all aliases for the same key). The description's note about omitting the key to list all keys is mirrored in the schema, so it adds little beyond what structured data already provides. Baseline 3 is appropriate since the schema does the heavy lifting.

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 ('Retrieve a value previously saved via remember, or list all saved keys') with concrete use examples (target ticker, address, research notes). It explicitly differentiates from siblings by naming remember (save) and forget (delete), so an agent can distinguish recall without inspecting other schemas.

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 clear context on when to use the tool ('look up context the agent stored earlier... without re-deriving it from scratch') and routes to alternatives ('Pair with remember to save, forget to delete'). It lacks an explicit when-not statement, but the scoping and sibling pairing make the intended usage unambiguous.

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