session.write

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

With no annotations, the description carries the full burden of behavioral disclosure. The verb 'persist' implies mutation, but nothing is said about side effects, idempotency (despite an idempotency_key parameter), overwrite semantics, or return behavior. The description offers only minimal context beyond the name.

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 a single short sentence with no fluff, which is structurally concise. However, it is so sparse that it borders on under-specification rather than effective conciseness. It is not front-loaded with the most important information because it contains almost no information.

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?

Given 10 parameters, an enum for entry types, and an output schema, the description is grossly incomplete. It does not explain what entries are, how client relates to sessions, or what the timestamps and IDs mean. An agent cannot confidently invoke this tool without external knowledge.

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 explain parameters, but it mentions none of the 10 parameters (client, entries, user_id, etc.). The schema itself has no descriptions, so the agent gets no meaning beyond field names and types. The description adds zero value here.

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 clear verb ('persist') and a resource ('structured context'), but 'structured context' is vague and doesn't convey the specific types of entries (summary, decision, fact, etc.) that the schema defines. It does not differentiate from sibling tools beyond implying a write operation, so an agent cannot fully understand the tool's role from the description alone.

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?

There is no guidance on when to use this tool versus alternatives such as memory.write or memory.propose. No conditions, prerequisites, or exclusions are mentioned, leaving the agent to infer usage from the schema and sibling names, which is insufficient.

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