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

Annotations only say readOnlyHint=false, idempotentHint=false, destructiveHint=false; the description adds genuinely new behavior: changes are session-scoped and do not touch the Territory Solution, render_ack is read at publish time so one-version-behind sent_unconfirmed is normal, render_ack_hint tells whether to reread or resend, camera persists until changed, and alignment switching does not refit. That is deep operational context an agent cannot get from structured fields.

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?

Dense but front-loaded: the mutation summary comes first, then session-vs-durable scoping, then the ack/camera caveats. Each sentence carries distinct information, though the ack and camera sentences are tightly packed and could be sectioned more readably.

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 6-param session-mutation tool with an output schema present, the description supplies the critical operational context: session scope, ack timing semantics, and camera source handling. The remaining gap is enumerating valid 'mode' values and the pending_job_reference contract, which neither schema nor description covers.

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 0% with 6 params, so the description carries the burden and does add real value: center is ordered [longitude, latitude] and zoom is bounded 0-24, plus camera's source enumeration (requested, session, map_config, viewer_current). However, it never explains the 'mode' parameter's permitted values, the shape/meaning of pending_job_reference, or map_session_id, leaving half the parameters semantically opaque.

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+resource ('Changes the open map's session state') and enumerates the exact facets it mutates: mode, active alignment, pending job reference, camera. It explicitly contrasts itself with configure_map, so an agent can separate the two without opening either 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?

Gives a clear selection rule — this is session-only, while configure_map sets a durable default view — which is exactly the decision an agent faces between these siblings. It stops short of stating full when-not conditions (e.g., whether a session must already exist), so it is clear context rather than an exhaustive routing guide.

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