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

With no annotations, the description carries full disclosure burden and does much of it: it explains that the AI rehydrates with prior decisions/chunk IDs/attachments, and highlights the context-size trade-off of include_document_html. It says nothing about the authorization parameter, permission requirements, or failure modes, which is the remaining behavioral 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?

Four sentences, most of which earn their place, with the core return payload and the continuation use case front-loaded. 'The AI rehydrates with full context of all prior decisions, chunk IDs, and attachments' partially repeats the earlier return inventory, so it is slightly longer than needed.

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?

An output schema exists, so return-value explanation is not strictly required, yet the description usefully characterizes what rehydration gives the agent. The main omission is any mention of the authorization parameter or access prerequisites for a session-history read.

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 coverage is 50%: focus_document_id and include_document_html are already documented in the schema, and the description largely restates the include_document_html behavior rather than adding new meaning. session_id and authorization have no description anywhere, and the description does not compensate for those gaps — baseline 3.

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?

Specific verb+resource ('get_session_history') with an explicit inventory of what is returned: message history, document HTML with chunk IDs, attachment list, and editor actions. It is clear what the tool retrieves, but it never contrasts itself with nearby siblings such as get_document_detail or list_sessions, so an agent must infer the boundary itself.

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?

States a clear usage context ('Use to continue editing a document you started in a prior session') and gives a conditional guideline for include_document_html=false when only the conversation is needed. It stops short of naming alternatives or exclusions, so it is clear context rather than full when/when-not routing.

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