memory_pin

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

With no annotations present, the description carries the full burden, and it delivers a key downstream behavior: SessionStart injects pinned notes first. That tells the agent the real effect of pinning and the injection ordering. It still omits persistence/permission semantics, but the core behavioral payoff is disclosed.

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 tight sentence with the action front-loaded and the downstream effect attached. Every clause earns its place with no redundancy.

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 two-parameter tool with no output schema, the description covers purpose and effect reasonably. The gap is the unexplained required node_id and no mention of what happens for an invalid id or whether pinning is idempotent, which a 0%-coverage schema leaves the description responsible for.

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 0%, so the description must compensate. It does clarify the 'pinned' boolean by framing the tool as pin-or-unpin, but the required node_id parameter is never mentioned or explained, leaving the most important argument undocumented in both schema and description.

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 (pin/unpin) on a specific resource (a note), and the parenthetical 'or unpin' immediately clarifies the bidirectional nature. The pinning operation is distinct from siblings like memory_write and memory_recall, so an agent can select it without ambiguity.

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 phrase 'the user wants in every session' implies the selection criterion for pinning, which is useful context. However, it names no alternatives (e.g., memory_write for one-off notes) and gives no explicit when-not guidance, so routing is left partly to inference.

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