session_end

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 for what is likely a mutating operation. It discloses that the session's status becomes 'completed' or 'failed' but doesn't address whether the operation is idempotent, reversible, whether it can be called multiple times, whether it affects in-flight operations, or what happens to the session's data afterward. For a tool that presumably mutates session state, this is a significant gap.

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?

One sentence, front-loaded with the action, with zero extraneous words. Every word earns its place, and the entire behavioral essence is captured in eight words.

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 tool of moderate complexity (3 flat params, no nesting, no enums), the description is mostly adequate but leaves some contextual questions open. Given the tool's position among 23 siblings including session_start and memory_checkpoint, some guidance on the session lifecycle would help agents distinguish when this tool versus a sibling is appropriate. The output schema covers return values, so its omission from the description is acceptable.

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 was expected to compensate. It does meaningfully clarify the 'status' parameter by naming its two valid values ('completed or failed'), which aligns with and augments the schema's bare default of 'completed'. However, it provides no additional meaning for 'agent_name' or 'session_id' — such as whether session_id comes from a session_start call or how to obtain it.

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 uses a specific verb ('mark'), a clear resource ('memory session'), and discloses the two possible outcome states ('completed or failed'). It clearly differentiates from sibling session_start by indicating this is the terminal operation, making the purpose immediately understandable without opening the schema.

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?

Usage context is only implied: an agent can reasonably infer this is called when a session's work is finished, contrasting with session_start. However, there is no explicit guidance on when not to use it, prerequisites (e.g., must have an active session, must use a session_id from a prior call), or differentiation from related siblings like memory_checkpoint or memory_bootstrap.

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