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Equation 5 · Part 7 · How Tool Protocols and the Model Context Protocol Actually Work

=

at=πθ(ht∣Tt),ot=Call(at),ht+1=ht⊕(at, ot)a_t = \pi_\theta(h_t \mid \mathcal{T}_t), \qquad o_t = \mathrm{Call}(a_t), \qquad h_{t+1} = h_t \oplus (a_t,\, o_t)
=

What this part means

The expressions on both sides represent the same quantity under the stated assumptions.

Its job in the formula

The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.

The passage around this formula

It helps to write the whole loop down once, because the assumption buried in it is the one the rest of this article is about: at=πθ(ht∣Tt),ot=Call(at),ht+1=ht⊕(at, ot)a_t = \pi_\theta(h_t \mid \mathcal{T}_t), \qquad o_t = \mathrm{Call}(a_t), \qquad h_{t+1} = h_t \oplus (a_t,\, o_t). Here Tt\mathcal{T}_t is the tool set most recently returned by tools/list , each member carrying its own schema; πθ\pi_\theta is the model, which is expected — but not forced by anything outside its own training — to emit a call ata_t whose name and arguments validate against some tool in Tt\mathcal{T}_t ; Call\mathrm{Call} is dispatch through the client to the server and back, exactly as described above; and ht+1h_{t+1} is the context the model reasons over on the next step, built by appending the call and its result to what came before. The assumption is in…

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Learn the underlying idea

An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.

Open the illustrated equality: what the equals sign claims guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.